[Concept] [PATCH 03/17] ext4l: bring in mballoc.c

From: Simon Glass <simon.glass@canonical.com> Copy mballoc.c from Linux v6.18 fs/ext4 directory. This file implements the multiblock allocator for efficient block allocation. Co-developed-by: Claude Opus 4.5 <noreply@anthropic.com> --- fs/ext4l/mballoc.c | 7175 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 7175 insertions(+) create mode 100644 fs/ext4l/mballoc.c diff --git a/fs/ext4l/mballoc.c b/fs/ext4l/mballoc.c new file mode 100644 index 00000000000..9087183602e --- /dev/null +++ b/fs/ext4l/mballoc.c @@ -0,0 +1,7175 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com + * Written by Alex Tomas <alex@clusterfs.com> + */ + + +/* + * mballoc.c contains the multiblocks allocation routines + */ + +#include "ext4_jbd2.h" +#include "mballoc.h" +#include <linux/log2.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/nospec.h> +#include <linux/backing-dev.h> +#include <linux/freezer.h> +#include <trace/events/ext4.h> +#include <kunit/static_stub.h> + +/* + * MUSTDO: + * - test ext4_ext_search_left() and ext4_ext_search_right() + * - search for metadata in few groups + * + * TODO v4: + * - normalization should take into account whether file is still open + * - discard preallocations if no free space left (policy?) + * - don't normalize tails + * - quota + * - reservation for superuser + * + * TODO v3: + * - bitmap read-ahead (proposed by Oleg Drokin aka green) + * - track min/max extents in each group for better group selection + * - mb_mark_used() may allocate chunk right after splitting buddy + * - tree of groups sorted by number of free blocks + * - error handling + */ + +/* + * The allocation request involve request for multiple number of blocks + * near to the goal(block) value specified. + * + * During initialization phase of the allocator we decide to use the + * group preallocation or inode preallocation depending on the size of + * the file. The size of the file could be the resulting file size we + * would have after allocation, or the current file size, which ever + * is larger. If the size is less than sbi->s_mb_stream_request we + * select to use the group preallocation. The default value of + * s_mb_stream_request is 16 blocks. This can also be tuned via + * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in + * terms of number of blocks. + * + * The main motivation for having small file use group preallocation is to + * ensure that we have small files closer together on the disk. + * + * First stage the allocator looks at the inode prealloc list, + * ext4_inode_info->i_prealloc_list, which contains list of prealloc + * spaces for this particular inode. The inode prealloc space is + * represented as: + * + * pa_lstart -> the logical start block for this prealloc space + * pa_pstart -> the physical start block for this prealloc space + * pa_len -> length for this prealloc space (in clusters) + * pa_free -> free space available in this prealloc space (in clusters) + * + * The inode preallocation space is used looking at the _logical_ start + * block. If only the logical file block falls within the range of prealloc + * space we will consume the particular prealloc space. This makes sure that + * we have contiguous physical blocks representing the file blocks + * + * The important thing to be noted in case of inode prealloc space is that + * we don't modify the values associated to inode prealloc space except + * pa_free. + * + * If we are not able to find blocks in the inode prealloc space and if we + * have the group allocation flag set then we look at the locality group + * prealloc space. These are per CPU prealloc list represented as + * + * ext4_sb_info.s_locality_groups[smp_processor_id()] + * + * The reason for having a per cpu locality group is to reduce the contention + * between CPUs. It is possible to get scheduled at this point. + * + * The locality group prealloc space is used looking at whether we have + * enough free space (pa_free) within the prealloc space. + * + * If we can't allocate blocks via inode prealloc or/and locality group + * prealloc then we look at the buddy cache. The buddy cache is represented + * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets + * mapped to the buddy and bitmap information regarding different + * groups. The buddy information is attached to buddy cache inode so that + * we can access them through the page cache. The information regarding + * each group is loaded via ext4_mb_load_buddy. The information involve + * block bitmap and buddy information. The information are stored in the + * inode as: + * + * { page } + * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]... + * + * + * one block each for bitmap and buddy information. So for each group we + * take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE / + * blocksize) blocks. So it can have information regarding groups_per_page + * which is blocks_per_page/2 + * + * The buddy cache inode is not stored on disk. The inode is thrown + * away when the filesystem is unmounted. + * + * We look for count number of blocks in the buddy cache. If we were able + * to locate that many free blocks we return with additional information + * regarding rest of the contiguous physical block available + * + * Before allocating blocks via buddy cache we normalize the request + * blocks. This ensure we ask for more blocks that we needed. The extra + * blocks that we get after allocation is added to the respective prealloc + * list. In case of inode preallocation we follow a list of heuristics + * based on file size. This can be found in ext4_mb_normalize_request. If + * we are doing a group prealloc we try to normalize the request to + * sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is + * dependent on the cluster size; for non-bigalloc file systems, it is + * 512 blocks. This can be tuned via + * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in + * terms of number of blocks. If we have mounted the file system with -O + * stripe=<value> option the group prealloc request is normalized to the + * smallest multiple of the stripe value (sbi->s_stripe) which is + * greater than the default mb_group_prealloc. + * + * If "mb_optimize_scan" mount option is set, we maintain in memory group info + * structures in two data structures: + * + * 1) Array of largest free order xarrays (sbi->s_mb_largest_free_orders) + * + * Locking: Writers use xa_lock, readers use rcu_read_lock. + * + * This is an array of xarrays where the index in the array represents the + * largest free order in the buddy bitmap of the participating group infos of + * that xarray. So, there are exactly MB_NUM_ORDERS(sb) (which means total + * number of buddy bitmap orders possible) number of xarrays. Group-infos are + * placed in appropriate xarrays. + * + * 2) Average fragment size xarrays (sbi->s_mb_avg_fragment_size) + * + * Locking: Writers use xa_lock, readers use rcu_read_lock. + * + * This is an array of xarrays where in the i-th xarray there are groups with + * average fragment size >= 2^i and < 2^(i+1). The average fragment size + * is computed as ext4_group_info->bb_free / ext4_group_info->bb_fragments. + * Note that we don't bother with a special xarray for completely empty + * groups so we only have MB_NUM_ORDERS(sb) xarrays. Group-infos are placed + * in appropriate xarrays. + * + * In xarray, the index is the block group number, the value is the block group + * information, and a non-empty value indicates the block group is present in + * the current xarray. + * + * When "mb_optimize_scan" mount option is set, mballoc consults the above data + * structures to decide the order in which groups are to be traversed for + * fulfilling an allocation request. + * + * At CR_POWER2_ALIGNED , we look for groups which have the largest_free_order + * >= the order of the request. We directly look at the largest free order list + * in the data structure (1) above where largest_free_order = order of the + * request. If that list is empty, we look at remaining list in the increasing + * order of largest_free_order. This allows us to perform CR_POWER2_ALIGNED + * lookup in O(1) time. + * + * At CR_GOAL_LEN_FAST, we only consider groups where + * average fragment size > request size. So, we lookup a group which has average + * fragment size just above or equal to request size using our average fragment + * size group lists (data structure 2) in O(1) time. + * + * At CR_BEST_AVAIL_LEN, we aim to optimize allocations which can't be satisfied + * in CR_GOAL_LEN_FAST. The fact that we couldn't find a group in + * CR_GOAL_LEN_FAST suggests that there is no BG that has avg + * fragment size > goal length. So before falling to the slower + * CR_GOAL_LEN_SLOW, in CR_BEST_AVAIL_LEN we proactively trim goal length and + * then use the same fragment lists as CR_GOAL_LEN_FAST to find a BG with a big + * enough average fragment size. This increases the chances of finding a + * suitable block group in O(1) time and results in faster allocation at the + * cost of reduced size of allocation. + * + * If "mb_optimize_scan" mount option is not set, mballoc traverses groups in + * linear order which requires O(N) search time for each CR_POWER2_ALIGNED and + * CR_GOAL_LEN_FAST phase. + * + * The regular allocator (using the buddy cache) supports a few tunables. + * + * /sys/fs/ext4/<partition>/mb_min_to_scan + * /sys/fs/ext4/<partition>/mb_max_to_scan + * /sys/fs/ext4/<partition>/mb_order2_req + * /sys/fs/ext4/<partition>/mb_max_linear_groups + * + * The regular allocator uses buddy scan only if the request len is power of + * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The + * value of s_mb_order2_reqs can be tuned via + * /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to + * stripe size (sbi->s_stripe), we try to search for contiguous block in + * stripe size. This should result in better allocation on RAID setups. If + * not, we search in the specific group using bitmap for best extents. The + * tunable min_to_scan and max_to_scan control the behaviour here. + * min_to_scan indicate how long the mballoc __must__ look for a best + * extent and max_to_scan indicates how long the mballoc __can__ look for a + * best extent in the found extents. Searching for the blocks starts with + * the group specified as the goal value in allocation context via + * ac_g_ex. Each group is first checked based on the criteria whether it + * can be used for allocation. ext4_mb_good_group explains how the groups are + * checked. + * + * When "mb_optimize_scan" is turned on, as mentioned above, the groups may not + * get traversed linearly. That may result in subsequent allocations being not + * close to each other. And so, the underlying device may get filled up in a + * non-linear fashion. While that may not matter on non-rotational devices, for + * rotational devices that may result in higher seek times. "mb_max_linear_groups" + * tells mballoc how many groups mballoc should search linearly before + * performing consulting above data structures for more efficient lookups. For + * non rotational devices, this value defaults to 0 and for rotational devices + * this is set to MB_DEFAULT_LINEAR_LIMIT. + * + * Both the prealloc space are getting populated as above. So for the first + * request we will hit the buddy cache which will result in this prealloc + * space getting filled. The prealloc space is then later used for the + * subsequent request. + */ + +/* + * mballoc operates on the following data: + * - on-disk bitmap + * - in-core buddy (actually includes buddy and bitmap) + * - preallocation descriptors (PAs) + * + * there are two types of preallocations: + * - inode + * assiged to specific inode and can be used for this inode only. + * it describes part of inode's space preallocated to specific + * physical blocks. any block from that preallocated can be used + * independent. the descriptor just tracks number of blocks left + * unused. so, before taking some block from descriptor, one must + * make sure corresponded logical block isn't allocated yet. this + * also means that freeing any block within descriptor's range + * must discard all preallocated blocks. + * - locality group + * assigned to specific locality group which does not translate to + * permanent set of inodes: inode can join and leave group. space + * from this type of preallocation can be used for any inode. thus + * it's consumed from the beginning to the end. + * + * relation between them can be expressed as: + * in-core buddy = on-disk bitmap + preallocation descriptors + * + * this mean blocks mballoc considers used are: + * - allocated blocks (persistent) + * - preallocated blocks (non-persistent) + * + * consistency in mballoc world means that at any time a block is either + * free or used in ALL structures. notice: "any time" should not be read + * literally -- time is discrete and delimited by locks. + * + * to keep it simple, we don't use block numbers, instead we count number of + * blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA. + * + * all operations can be expressed as: + * - init buddy: buddy = on-disk + PAs + * - new PA: buddy += N; PA = N + * - use inode PA: on-disk += N; PA -= N + * - discard inode PA buddy -= on-disk - PA; PA = 0 + * - use locality group PA on-disk += N; PA -= N + * - discard locality group PA buddy -= PA; PA = 0 + * note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap + * is used in real operation because we can't know actual used + * bits from PA, only from on-disk bitmap + * + * if we follow this strict logic, then all operations above should be atomic. + * given some of them can block, we'd have to use something like semaphores + * killing performance on high-end SMP hardware. let's try to relax it using + * the following knowledge: + * 1) if buddy is referenced, it's already initialized + * 2) while block is used in buddy and the buddy is referenced, + * nobody can re-allocate that block + * 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has + * bit set and PA claims same block, it's OK. IOW, one can set bit in + * on-disk bitmap if buddy has same bit set or/and PA covers corresponded + * block + * + * so, now we're building a concurrency table: + * - init buddy vs. + * - new PA + * blocks for PA are allocated in the buddy, buddy must be referenced + * until PA is linked to allocation group to avoid concurrent buddy init + * - use inode PA + * we need to make sure that either on-disk bitmap or PA has uptodate data + * given (3) we care that PA-=N operation doesn't interfere with init + * - discard inode PA + * the simplest way would be to have buddy initialized by the discard + * - use locality group PA + * again PA-=N must be serialized with init + * - discard locality group PA + * the simplest way would be to have buddy initialized by the discard + * - new PA vs. + * - use inode PA + * i_data_sem serializes them + * - discard inode PA + * discard process must wait until PA isn't used by another process + * - use locality group PA + * some mutex should serialize them + * - discard locality group PA + * discard process must wait until PA isn't used by another process + * - use inode PA + * - use inode PA + * i_data_sem or another mutex should serializes them + * - discard inode PA + * discard process must wait until PA isn't used by another process + * - use locality group PA + * nothing wrong here -- they're different PAs covering different blocks + * - discard locality group PA + * discard process must wait until PA isn't used by another process + * + * now we're ready to make few consequences: + * - PA is referenced and while it is no discard is possible + * - PA is referenced until block isn't marked in on-disk bitmap + * - PA changes only after on-disk bitmap + * - discard must not compete with init. either init is done before + * any discard or they're serialized somehow + * - buddy init as sum of on-disk bitmap and PAs is done atomically + * + * a special case when we've used PA to emptiness. no need to modify buddy + * in this case, but we should care about concurrent init + * + */ + + /* + * Logic in few words: + * + * - allocation: + * load group + * find blocks + * mark bits in on-disk bitmap + * release group + * + * - use preallocation: + * find proper PA (per-inode or group) + * load group + * mark bits in on-disk bitmap + * release group + * release PA + * + * - free: + * load group + * mark bits in on-disk bitmap + * release group + * + * - discard preallocations in group: + * mark PAs deleted + * move them onto local list + * load on-disk bitmap + * load group + * remove PA from object (inode or locality group) + * mark free blocks in-core + * + * - discard inode's preallocations: + */ + +/* + * Locking rules + * + * Locks: + * - bitlock on a group (group) + * - object (inode/locality) (object) + * - per-pa lock (pa) + * - cr_power2_aligned lists lock (cr_power2_aligned) + * - cr_goal_len_fast lists lock (cr_goal_len_fast) + * + * Paths: + * - new pa + * object + * group + * + * - find and use pa: + * pa + * + * - release consumed pa: + * pa + * group + * object + * + * - generate in-core bitmap: + * group + * pa + * + * - discard all for given object (inode, locality group): + * object + * pa + * group + * + * - discard all for given group: + * group + * pa + * group + * object + * + * - allocation path (ext4_mb_regular_allocator) + * group + * cr_power2_aligned/cr_goal_len_fast + */ +static struct kmem_cache *ext4_pspace_cachep; +static struct kmem_cache *ext4_ac_cachep; +static struct kmem_cache *ext4_free_data_cachep; + +/* We create slab caches for groupinfo data structures based on the + * superblock block size. There will be one per mounted filesystem for + * each unique s_blocksize_bits */ +#define NR_GRPINFO_CACHES 8 +static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES]; + +static const char * const ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = { + "ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k", + "ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k", + "ext4_groupinfo_64k", "ext4_groupinfo_128k" +}; + +static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, + ext4_group_t group); +static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac); + +static int ext4_mb_scan_group(struct ext4_allocation_context *ac, + ext4_group_t group); + +static int ext4_try_to_trim_range(struct super_block *sb, + struct ext4_buddy *e4b, ext4_grpblk_t start, + ext4_grpblk_t max, ext4_grpblk_t minblocks); + +/* + * The algorithm using this percpu seq counter goes below: + * 1. We sample the percpu discard_pa_seq counter before trying for block + * allocation in ext4_mb_new_blocks(). + * 2. We increment this percpu discard_pa_seq counter when we either allocate + * or free these blocks i.e. while marking those blocks as used/free in + * mb_mark_used()/mb_free_blocks(). + * 3. We also increment this percpu seq counter when we successfully identify + * that the bb_prealloc_list is not empty and hence proceed for discarding + * of those PAs inside ext4_mb_discard_group_preallocations(). + * + * Now to make sure that the regular fast path of block allocation is not + * affected, as a small optimization we only sample the percpu seq counter + * on that cpu. Only when the block allocation fails and when freed blocks + * found were 0, that is when we sample percpu seq counter for all cpus using + * below function ext4_get_discard_pa_seq_sum(). This happens after making + * sure that all the PAs on grp->bb_prealloc_list got freed or if it's empty. + */ +static DEFINE_PER_CPU(u64, discard_pa_seq); +static inline u64 ext4_get_discard_pa_seq_sum(void) +{ + int __cpu; + u64 __seq = 0; + + for_each_possible_cpu(__cpu) + __seq += per_cpu(discard_pa_seq, __cpu); + return __seq; +} + +static inline void *mb_correct_addr_and_bit(int *bit, void *addr) +{ +#if BITS_PER_LONG == 64 + *bit += ((unsigned long) addr & 7UL) << 3; + addr = (void *) ((unsigned long) addr & ~7UL); +#elif BITS_PER_LONG == 32 + *bit += ((unsigned long) addr & 3UL) << 3; + addr = (void *) ((unsigned long) addr & ~3UL); +#else +#error "how many bits you are?!" +#endif + return addr; +} + +static inline int mb_test_bit(int bit, void *addr) +{ + /* + * ext4_test_bit on architecture like powerpc + * needs unsigned long aligned address + */ + addr = mb_correct_addr_and_bit(&bit, addr); + return ext4_test_bit(bit, addr); +} + +static inline void mb_set_bit(int bit, void *addr) +{ + addr = mb_correct_addr_and_bit(&bit, addr); + ext4_set_bit(bit, addr); +} + +static inline void mb_clear_bit(int bit, void *addr) +{ + addr = mb_correct_addr_and_bit(&bit, addr); + ext4_clear_bit(bit, addr); +} + +static inline int mb_test_and_clear_bit(int bit, void *addr) +{ + addr = mb_correct_addr_and_bit(&bit, addr); + return ext4_test_and_clear_bit(bit, addr); +} + +static inline int mb_find_next_zero_bit(void *addr, int max, int start) +{ + int fix = 0, ret, tmpmax; + addr = mb_correct_addr_and_bit(&fix, addr); + tmpmax = max + fix; + start += fix; + + ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix; + if (ret > max) + return max; + return ret; +} + +static inline int mb_find_next_bit(void *addr, int max, int start) +{ + int fix = 0, ret, tmpmax; + addr = mb_correct_addr_and_bit(&fix, addr); + tmpmax = max + fix; + start += fix; + + ret = ext4_find_next_bit(addr, tmpmax, start) - fix; + if (ret > max) + return max; + return ret; +} + +static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max) +{ + char *bb; + + BUG_ON(e4b->bd_bitmap == e4b->bd_buddy); + BUG_ON(max == NULL); + + if (order > e4b->bd_blkbits + 1) { + *max = 0; + return NULL; + } + + /* at order 0 we see each particular block */ + if (order == 0) { + *max = 1 << (e4b->bd_blkbits + 3); + return e4b->bd_bitmap; + } + + bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order]; + *max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order]; + + return bb; +} + +#ifdef DOUBLE_CHECK +static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b, + int first, int count) +{ + int i; + struct super_block *sb = e4b->bd_sb; + + if (unlikely(e4b->bd_info->bb_bitmap == NULL)) + return; + assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group)); + for (i = 0; i < count; i++) { + if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) { + ext4_fsblk_t blocknr; + + blocknr = ext4_group_first_block_no(sb, e4b->bd_group); + blocknr += EXT4_C2B(EXT4_SB(sb), first + i); + ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + ext4_grp_locked_error(sb, e4b->bd_group, + inode ? inode->i_ino : 0, + blocknr, + "freeing block already freed " + "(bit %u)", + first + i); + } + mb_clear_bit(first + i, e4b->bd_info->bb_bitmap); + } +} + +static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count) +{ + int i; + + if (unlikely(e4b->bd_info->bb_bitmap == NULL)) + return; + assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group)); + for (i = 0; i < count; i++) { + BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap)); + mb_set_bit(first + i, e4b->bd_info->bb_bitmap); + } +} + +static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap) +{ + if (unlikely(e4b->bd_info->bb_bitmap == NULL)) + return; + if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) { + unsigned char *b1, *b2; + int i; + b1 = (unsigned char *) e4b->bd_info->bb_bitmap; + b2 = (unsigned char *) bitmap; + for (i = 0; i < e4b->bd_sb->s_blocksize; i++) { + if (b1[i] != b2[i]) { + ext4_msg(e4b->bd_sb, KERN_ERR, + "corruption in group %u " + "at byte %u(%u): %x in copy != %x " + "on disk/prealloc", + e4b->bd_group, i, i * 8, b1[i], b2[i]); + BUG(); + } + } + } +} + +static void mb_group_bb_bitmap_alloc(struct super_block *sb, + struct ext4_group_info *grp, ext4_group_t group) +{ + struct buffer_head *bh; + + grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS); + if (!grp->bb_bitmap) + return; + + bh = ext4_read_block_bitmap(sb, group); + if (IS_ERR_OR_NULL(bh)) { + kfree(grp->bb_bitmap); + grp->bb_bitmap = NULL; + return; + } + + memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize); + put_bh(bh); +} + +static void mb_group_bb_bitmap_free(struct ext4_group_info *grp) +{ + kfree(grp->bb_bitmap); +} + +#else +static inline void mb_free_blocks_double(struct inode *inode, + struct ext4_buddy *e4b, int first, int count) +{ + return; +} +static inline void mb_mark_used_double(struct ext4_buddy *e4b, + int first, int count) +{ + return; +} +static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap) +{ + return; +} + +static inline void mb_group_bb_bitmap_alloc(struct super_block *sb, + struct ext4_group_info *grp, ext4_group_t group) +{ + return; +} + +static inline void mb_group_bb_bitmap_free(struct ext4_group_info *grp) +{ + return; +} +#endif + +#ifdef AGGRESSIVE_CHECK + +#define MB_CHECK_ASSERT(assert) \ +do { \ + if (!(assert)) { \ + printk(KERN_EMERG \ + "Assertion failure in %s() at %s:%d: \"%s\"\n", \ + function, file, line, # assert); \ + BUG(); \ + } \ +} while (0) + +static void __mb_check_buddy(struct ext4_buddy *e4b, char *file, + const char *function, int line) +{ + struct super_block *sb = e4b->bd_sb; + int order = e4b->bd_blkbits + 1; + int max; + int max2; + int i; + int j; + int k; + int count; + struct ext4_group_info *grp; + int fragments = 0; + int fstart; + struct list_head *cur; + void *buddy; + void *buddy2; + + if (e4b->bd_info->bb_check_counter++ % 10) + return; + + while (order > 1) { + buddy = mb_find_buddy(e4b, order, &max); + MB_CHECK_ASSERT(buddy); + buddy2 = mb_find_buddy(e4b, order - 1, &max2); + MB_CHECK_ASSERT(buddy2); + MB_CHECK_ASSERT(buddy != buddy2); + MB_CHECK_ASSERT(max * 2 == max2); + + count = 0; + for (i = 0; i < max; i++) { + + if (mb_test_bit(i, buddy)) { + /* only single bit in buddy2 may be 0 */ + if (!mb_test_bit(i << 1, buddy2)) { + MB_CHECK_ASSERT( + mb_test_bit((i<<1)+1, buddy2)); + } + continue; + } + + /* both bits in buddy2 must be 1 */ + MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2)); + MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2)); + + for (j = 0; j < (1 << order); j++) { + k = (i * (1 << order)) + j; + MB_CHECK_ASSERT( + !mb_test_bit(k, e4b->bd_bitmap)); + } + count++; + } + MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count); + order--; + } + + fstart = -1; + buddy = mb_find_buddy(e4b, 0, &max); + for (i = 0; i < max; i++) { + if (!mb_test_bit(i, buddy)) { + MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free); + if (fstart == -1) { + fragments++; + fstart = i; + } + continue; + } + fstart = -1; + /* check used bits only */ + for (j = 0; j < e4b->bd_blkbits + 1; j++) { + buddy2 = mb_find_buddy(e4b, j, &max2); + k = i >> j; + MB_CHECK_ASSERT(k < max2); + MB_CHECK_ASSERT(mb_test_bit(k, buddy2)); + } + } + MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info)); + MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments); + + grp = ext4_get_group_info(sb, e4b->bd_group); + if (!grp) + return; + list_for_each(cur, &grp->bb_prealloc_list) { + ext4_group_t groupnr; + struct ext4_prealloc_space *pa; + pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k); + MB_CHECK_ASSERT(groupnr == e4b->bd_group); + for (i = 0; i < pa->pa_len; i++) + MB_CHECK_ASSERT(mb_test_bit(k + i, buddy)); + } +} +#undef MB_CHECK_ASSERT +#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \ + __FILE__, __func__, __LINE__) +#else +#define mb_check_buddy(e4b) +#endif + +/* + * Divide blocks started from @first with length @len into + * smaller chunks with power of 2 blocks. + * Clear the bits in bitmap which the blocks of the chunk(s) covered, + * then increase bb_counters[] for corresponded chunk size. + */ +static void ext4_mb_mark_free_simple(struct super_block *sb, + void *buddy, ext4_grpblk_t first, ext4_grpblk_t len, + struct ext4_group_info *grp) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_grpblk_t min; + ext4_grpblk_t max; + ext4_grpblk_t chunk; + unsigned int border; + + BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb)); + + border = 2 << sb->s_blocksize_bits; + + while (len > 0) { + /* find how many blocks can be covered since this position */ + max = ffs(first | border) - 1; + + /* find how many blocks of power 2 we need to mark */ + min = fls(len) - 1; + + if (max < min) + min = max; + chunk = 1 << min; + + /* mark multiblock chunks only */ + grp->bb_counters[min]++; + if (min > 0) + mb_clear_bit(first >> min, + buddy + sbi->s_mb_offsets[min]); + + len -= chunk; + first += chunk; + } +} + +static int mb_avg_fragment_size_order(struct super_block *sb, ext4_grpblk_t len) +{ + int order; + + /* + * We don't bother with a special lists groups with only 1 block free + * extents and for completely empty groups. + */ + order = fls(len) - 2; + if (order < 0) + return 0; + if (order == MB_NUM_ORDERS(sb)) + order--; + if (WARN_ON_ONCE(order > MB_NUM_ORDERS(sb))) + order = MB_NUM_ORDERS(sb) - 1; + return order; +} + +/* Move group to appropriate avg_fragment_size list */ +static void +mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + int new, old; + + if (!test_opt2(sb, MB_OPTIMIZE_SCAN)) + return; + + old = grp->bb_avg_fragment_size_order; + new = grp->bb_fragments == 0 ? -1 : + mb_avg_fragment_size_order(sb, grp->bb_free / grp->bb_fragments); + if (new == old) + return; + + if (old >= 0) + xa_erase(&sbi->s_mb_avg_fragment_size[old], grp->bb_group); + + grp->bb_avg_fragment_size_order = new; + if (new >= 0) { + /* + * Cannot use __GFP_NOFAIL because we hold the group lock. + * Although allocation for insertion may fails, it's not fatal + * as we have linear traversal to fall back on. + */ + int err = xa_insert(&sbi->s_mb_avg_fragment_size[new], + grp->bb_group, grp, GFP_ATOMIC); + if (err) + mb_debug(sb, "insert group: %u to s_mb_avg_fragment_size[%d] failed, err %d", + grp->bb_group, new, err); + } +} + +static int ext4_mb_scan_groups_xa_range(struct ext4_allocation_context *ac, + struct xarray *xa, + ext4_group_t start, ext4_group_t end) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + enum criteria cr = ac->ac_criteria; + ext4_group_t ngroups = ext4_get_groups_count(sb); + unsigned long group = start; + struct ext4_group_info *grp; + + if (WARN_ON_ONCE(end > ngroups || start >= end)) + return 0; + + xa_for_each_range(xa, group, grp, start, end - 1) { + int err; + + if (sbi->s_mb_stats) + atomic64_inc(&sbi->s_bal_cX_groups_considered[cr]); + + err = ext4_mb_scan_group(ac, grp->bb_group); + if (err || ac->ac_status != AC_STATUS_CONTINUE) + return err; + + cond_resched(); + } + + return 0; +} + +/* + * Find a suitable group of given order from the largest free orders xarray. + */ +static inline int +ext4_mb_scan_groups_largest_free_order_range(struct ext4_allocation_context *ac, + int order, ext4_group_t start, + ext4_group_t end) +{ + struct xarray *xa = &EXT4_SB(ac->ac_sb)->s_mb_largest_free_orders[order]; + + if (xa_empty(xa)) + return 0; + + return ext4_mb_scan_groups_xa_range(ac, xa, start, end); +} + +/* + * Choose next group by traversing largest_free_order lists. Updates *new_cr if + * cr level needs an update. + */ +static int ext4_mb_scan_groups_p2_aligned(struct ext4_allocation_context *ac, + ext4_group_t group) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + int i; + int ret = 0; + ext4_group_t start, end; + + start = group; + end = ext4_get_groups_count(ac->ac_sb); +wrap_around: + for (i = ac->ac_2order; i < MB_NUM_ORDERS(ac->ac_sb); i++) { + ret = ext4_mb_scan_groups_largest_free_order_range(ac, i, + start, end); + if (ret || ac->ac_status != AC_STATUS_CONTINUE) + return ret; + } + if (start) { + end = start; + start = 0; + goto wrap_around; + } + + if (sbi->s_mb_stats) + atomic64_inc(&sbi->s_bal_cX_failed[ac->ac_criteria]); + + /* Increment cr and search again if no group is found */ + ac->ac_criteria = CR_GOAL_LEN_FAST; + return ret; +} + +/* + * Find a suitable group of given order from the average fragments xarray. + */ +static int +ext4_mb_scan_groups_avg_frag_order_range(struct ext4_allocation_context *ac, + int order, ext4_group_t start, + ext4_group_t end) +{ + struct xarray *xa = &EXT4_SB(ac->ac_sb)->s_mb_avg_fragment_size[order]; + + if (xa_empty(xa)) + return 0; + + return ext4_mb_scan_groups_xa_range(ac, xa, start, end); +} + +/* + * Choose next group by traversing average fragment size list of suitable + * order. Updates *new_cr if cr level needs an update. + */ +static int ext4_mb_scan_groups_goal_fast(struct ext4_allocation_context *ac, + ext4_group_t group) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + int i, ret = 0; + ext4_group_t start, end; + + start = group; + end = ext4_get_groups_count(ac->ac_sb); +wrap_around: + i = mb_avg_fragment_size_order(ac->ac_sb, ac->ac_g_ex.fe_len); + for (; i < MB_NUM_ORDERS(ac->ac_sb); i++) { + ret = ext4_mb_scan_groups_avg_frag_order_range(ac, i, + start, end); + if (ret || ac->ac_status != AC_STATUS_CONTINUE) + return ret; + } + if (start) { + end = start; + start = 0; + goto wrap_around; + } + + if (sbi->s_mb_stats) + atomic64_inc(&sbi->s_bal_cX_failed[ac->ac_criteria]); + /* + * CR_BEST_AVAIL_LEN works based on the concept that we have + * a larger normalized goal len request which can be trimmed to + * a smaller goal len such that it can still satisfy original + * request len. However, allocation request for non-regular + * files never gets normalized. + * See function ext4_mb_normalize_request() (EXT4_MB_HINT_DATA). + */ + if (ac->ac_flags & EXT4_MB_HINT_DATA) + ac->ac_criteria = CR_BEST_AVAIL_LEN; + else + ac->ac_criteria = CR_GOAL_LEN_SLOW; + + return ret; +} + +/* + * We couldn't find a group in CR_GOAL_LEN_FAST so try to find the highest free fragment + * order we have and proactively trim the goal request length to that order to + * find a suitable group faster. + * + * This optimizes allocation speed at the cost of slightly reduced + * preallocations. However, we make sure that we don't trim the request too + * much and fall to CR_GOAL_LEN_SLOW in that case. + */ +static int ext4_mb_scan_groups_best_avail(struct ext4_allocation_context *ac, + ext4_group_t group) +{ + int ret = 0; + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + int i, order, min_order; + unsigned long num_stripe_clusters = 0; + ext4_group_t start, end; + + /* + * mb_avg_fragment_size_order() returns order in a way that makes + * retrieving back the length using (1 << order) inaccurate. Hence, use + * fls() instead since we need to know the actual length while modifying + * goal length. + */ + order = fls(ac->ac_g_ex.fe_len) - 1; + if (WARN_ON_ONCE(order - 1 > MB_NUM_ORDERS(ac->ac_sb))) + order = MB_NUM_ORDERS(ac->ac_sb); + min_order = order - sbi->s_mb_best_avail_max_trim_order; + if (min_order < 0) + min_order = 0; + + if (sbi->s_stripe > 0) { + /* + * We are assuming that stripe size is always a multiple of + * cluster ratio otherwise __ext4_fill_super exists early. + */ + num_stripe_clusters = EXT4_NUM_B2C(sbi, sbi->s_stripe); + if (1 << min_order < num_stripe_clusters) + /* + * We consider 1 order less because later we round + * up the goal len to num_stripe_clusters + */ + min_order = fls(num_stripe_clusters) - 1; + } + + if (1 << min_order < ac->ac_o_ex.fe_len) + min_order = fls(ac->ac_o_ex.fe_len); + + start = group; + end = ext4_get_groups_count(ac->ac_sb); +wrap_around: + for (i = order; i >= min_order; i--) { + int frag_order; + /* + * Scale down goal len to make sure we find something + * in the free fragments list. Basically, reduce + * preallocations. + */ + ac->ac_g_ex.fe_len = 1 << i; + + if (num_stripe_clusters > 0) { + /* + * Try to round up the adjusted goal length to + * stripe size (in cluster units) multiple for + * efficiency. + */ + ac->ac_g_ex.fe_len = roundup(ac->ac_g_ex.fe_len, + num_stripe_clusters); + } + + frag_order = mb_avg_fragment_size_order(ac->ac_sb, + ac->ac_g_ex.fe_len); + + ret = ext4_mb_scan_groups_avg_frag_order_range(ac, frag_order, + start, end); + if (ret || ac->ac_status != AC_STATUS_CONTINUE) + return ret; + } + if (start) { + end = start; + start = 0; + goto wrap_around; + } + + /* Reset goal length to original goal length before falling into CR_GOAL_LEN_SLOW */ + ac->ac_g_ex.fe_len = ac->ac_orig_goal_len; + if (sbi->s_mb_stats) + atomic64_inc(&sbi->s_bal_cX_failed[ac->ac_criteria]); + ac->ac_criteria = CR_GOAL_LEN_SLOW; + + return ret; +} + +static inline int should_optimize_scan(struct ext4_allocation_context *ac) +{ + if (unlikely(!test_opt2(ac->ac_sb, MB_OPTIMIZE_SCAN))) + return 0; + if (ac->ac_criteria >= CR_GOAL_LEN_SLOW) + return 0; + if (!ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) + return 0; + return 1; +} + +/* + * next linear group for allocation. + */ +static void next_linear_group(ext4_group_t *group, ext4_group_t ngroups) +{ + /* + * Artificially restricted ngroups for non-extent + * files makes group > ngroups possible on first loop. + */ + *group = *group + 1 >= ngroups ? 0 : *group + 1; +} + +static int ext4_mb_scan_groups_linear(struct ext4_allocation_context *ac, + ext4_group_t ngroups, ext4_group_t *start, ext4_group_t count) +{ + int ret, i; + enum criteria cr = ac->ac_criteria; + struct super_block *sb = ac->ac_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_group_t group = *start; + + for (i = 0; i < count; i++, next_linear_group(&group, ngroups)) { + ret = ext4_mb_scan_group(ac, group); + if (ret || ac->ac_status != AC_STATUS_CONTINUE) + return ret; + cond_resched(); + } + + *start = group; + if (count == ngroups) + ac->ac_criteria++; + + /* Processed all groups and haven't found blocks */ + if (sbi->s_mb_stats && i == ngroups) + atomic64_inc(&sbi->s_bal_cX_failed[cr]); + + return 0; +} + +static int ext4_mb_scan_groups(struct ext4_allocation_context *ac) +{ + int ret = 0; + ext4_group_t start; + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + ext4_group_t ngroups = ext4_get_groups_count(ac->ac_sb); + + /* non-extent files are limited to low blocks/groups */ + if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS))) + ngroups = sbi->s_blockfile_groups; + + /* searching for the right group start from the goal value specified */ + start = ac->ac_g_ex.fe_group; + ac->ac_prefetch_grp = start; + ac->ac_prefetch_nr = 0; + + if (!should_optimize_scan(ac)) + return ext4_mb_scan_groups_linear(ac, ngroups, &start, ngroups); + + /* + * Optimized scanning can return non adjacent groups which can cause + * seek overhead for rotational disks. So try few linear groups before + * trying optimized scan. + */ + if (sbi->s_mb_max_linear_groups) + ret = ext4_mb_scan_groups_linear(ac, ngroups, &start, + sbi->s_mb_max_linear_groups); + if (ret || ac->ac_status != AC_STATUS_CONTINUE) + return ret; + + switch (ac->ac_criteria) { + case CR_POWER2_ALIGNED: + return ext4_mb_scan_groups_p2_aligned(ac, start); + case CR_GOAL_LEN_FAST: + return ext4_mb_scan_groups_goal_fast(ac, start); + case CR_BEST_AVAIL_LEN: + return ext4_mb_scan_groups_best_avail(ac, start); + default: + /* + * TODO: For CR_GOAL_LEN_SLOW, we can arrange groups in an + * rb tree sorted by bb_free. But until that happens, we should + * never come here. + */ + WARN_ON(1); + } + + return 0; +} + +/* + * Cache the order of the largest free extent we have available in this block + * group. + */ +static void +mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + int new, old = grp->bb_largest_free_order; + + for (new = MB_NUM_ORDERS(sb) - 1; new >= 0; new--) + if (grp->bb_counters[new] > 0) + break; + + /* No need to move between order lists? */ + if (new == old) + return; + + if (old >= 0) { + struct xarray *xa = &sbi->s_mb_largest_free_orders[old]; + + if (!xa_empty(xa) && xa_load(xa, grp->bb_group)) + xa_erase(xa, grp->bb_group); + } + + grp->bb_largest_free_order = new; + if (test_opt2(sb, MB_OPTIMIZE_SCAN) && new >= 0 && grp->bb_free) { + /* + * Cannot use __GFP_NOFAIL because we hold the group lock. + * Although allocation for insertion may fails, it's not fatal + * as we have linear traversal to fall back on. + */ + int err = xa_insert(&sbi->s_mb_largest_free_orders[new], + grp->bb_group, grp, GFP_ATOMIC); + if (err) + mb_debug(sb, "insert group: %u to s_mb_largest_free_orders[%d] failed, err %d", + grp->bb_group, new, err); + } +} + +static noinline_for_stack +void ext4_mb_generate_buddy(struct super_block *sb, + void *buddy, void *bitmap, ext4_group_t group, + struct ext4_group_info *grp) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb); + ext4_grpblk_t i = 0; + ext4_grpblk_t first; + ext4_grpblk_t len; + unsigned free = 0; + unsigned fragments = 0; + unsigned long long period = get_cycles(); + + /* initialize buddy from bitmap which is aggregation + * of on-disk bitmap and preallocations */ + i = mb_find_next_zero_bit(bitmap, max, 0); + grp->bb_first_free = i; + while (i < max) { + fragments++; + first = i; + i = mb_find_next_bit(bitmap, max, i); + len = i - first; + free += len; + if (len > 1) + ext4_mb_mark_free_simple(sb, buddy, first, len, grp); + else + grp->bb_counters[0]++; + if (i < max) + i = mb_find_next_zero_bit(bitmap, max, i); + } + grp->bb_fragments = fragments; + + if (free != grp->bb_free) { + ext4_grp_locked_error(sb, group, 0, 0, + "block bitmap and bg descriptor " + "inconsistent: %u vs %u free clusters", + free, grp->bb_free); + /* + * If we intend to continue, we consider group descriptor + * corrupt and update bb_free using bitmap value + */ + grp->bb_free = free; + ext4_mark_group_bitmap_corrupted(sb, group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + } + mb_set_largest_free_order(sb, grp); + mb_update_avg_fragment_size(sb, grp); + + clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state)); + + period = get_cycles() - period; + atomic_inc(&sbi->s_mb_buddies_generated); + atomic64_add(period, &sbi->s_mb_generation_time); +} + +static void mb_regenerate_buddy(struct ext4_buddy *e4b) +{ + int count; + int order = 1; + void *buddy; + + while ((buddy = mb_find_buddy(e4b, order++, &count))) + mb_set_bits(buddy, 0, count); + + e4b->bd_info->bb_fragments = 0; + memset(e4b->bd_info->bb_counters, 0, + sizeof(*e4b->bd_info->bb_counters) * + (e4b->bd_sb->s_blocksize_bits + 2)); + + ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy, + e4b->bd_bitmap, e4b->bd_group, e4b->bd_info); +} + +/* The buddy information is attached the buddy cache inode + * for convenience. The information regarding each group + * is loaded via ext4_mb_load_buddy. The information involve + * block bitmap and buddy information. The information are + * stored in the inode as + * + * { page } + * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]... + * + * + * one block each for bitmap and buddy information. + * So for each group we take up 2 blocks. A page can + * contain blocks_per_page (PAGE_SIZE / blocksize) blocks. + * So it can have information regarding groups_per_page which + * is blocks_per_page/2 + * + * Locking note: This routine takes the block group lock of all groups + * for this page; do not hold this lock when calling this routine! + */ + +static int ext4_mb_init_cache(struct folio *folio, char *incore, gfp_t gfp) +{ + ext4_group_t ngroups; + unsigned int blocksize; + int blocks_per_page; + int groups_per_page; + int err = 0; + int i; + ext4_group_t first_group, group; + int first_block; + struct super_block *sb; + struct buffer_head *bhs; + struct buffer_head **bh = NULL; + struct inode *inode; + char *data; + char *bitmap; + struct ext4_group_info *grinfo; + + inode = folio->mapping->host; + sb = inode->i_sb; + ngroups = ext4_get_groups_count(sb); + blocksize = i_blocksize(inode); + blocks_per_page = PAGE_SIZE / blocksize; + + mb_debug(sb, "init folio %lu\n", folio->index); + + groups_per_page = blocks_per_page >> 1; + if (groups_per_page == 0) + groups_per_page = 1; + + /* allocate buffer_heads to read bitmaps */ + if (groups_per_page > 1) { + i = sizeof(struct buffer_head *) * groups_per_page; + bh = kzalloc(i, gfp); + if (bh == NULL) + return -ENOMEM; + } else + bh = &bhs; + + first_group = folio->index * blocks_per_page / 2; + + /* read all groups the folio covers into the cache */ + for (i = 0, group = first_group; i < groups_per_page; i++, group++) { + if (group >= ngroups) + break; + + grinfo = ext4_get_group_info(sb, group); + if (!grinfo) + continue; + /* + * If page is uptodate then we came here after online resize + * which added some new uninitialized group info structs, so + * we must skip all initialized uptodate buddies on the folio, + * which may be currently in use by an allocating task. + */ + if (folio_test_uptodate(folio) && + !EXT4_MB_GRP_NEED_INIT(grinfo)) { + bh[i] = NULL; + continue; + } + bh[i] = ext4_read_block_bitmap_nowait(sb, group, false); + if (IS_ERR(bh[i])) { + err = PTR_ERR(bh[i]); + bh[i] = NULL; + goto out; + } + mb_debug(sb, "read bitmap for group %u\n", group); + } + + /* wait for I/O completion */ + for (i = 0, group = first_group; i < groups_per_page; i++, group++) { + int err2; + + if (!bh[i]) + continue; + err2 = ext4_wait_block_bitmap(sb, group, bh[i]); + if (!err) + err = err2; + } + + first_block = folio->index * blocks_per_page; + for (i = 0; i < blocks_per_page; i++) { + group = (first_block + i) >> 1; + if (group >= ngroups) + break; + + if (!bh[group - first_group]) + /* skip initialized uptodate buddy */ + continue; + + if (!buffer_verified(bh[group - first_group])) + /* Skip faulty bitmaps */ + continue; + err = 0; + + /* + * data carry information regarding this + * particular group in the format specified + * above + * + */ + data = folio_address(folio) + (i * blocksize); + bitmap = bh[group - first_group]->b_data; + + /* + * We place the buddy block and bitmap block + * close together + */ + grinfo = ext4_get_group_info(sb, group); + if (!grinfo) { + err = -EFSCORRUPTED; + goto out; + } + if ((first_block + i) & 1) { + /* this is block of buddy */ + BUG_ON(incore == NULL); + mb_debug(sb, "put buddy for group %u in folio %lu/%x\n", + group, folio->index, i * blocksize); + trace_ext4_mb_buddy_bitmap_load(sb, group); + grinfo->bb_fragments = 0; + memset(grinfo->bb_counters, 0, + sizeof(*grinfo->bb_counters) * + (MB_NUM_ORDERS(sb))); + /* + * incore got set to the group block bitmap below + */ + ext4_lock_group(sb, group); + /* init the buddy */ + memset(data, 0xff, blocksize); + ext4_mb_generate_buddy(sb, data, incore, group, grinfo); + ext4_unlock_group(sb, group); + incore = NULL; + } else { + /* this is block of bitmap */ + BUG_ON(incore != NULL); + mb_debug(sb, "put bitmap for group %u in folio %lu/%x\n", + group, folio->index, i * blocksize); + trace_ext4_mb_bitmap_load(sb, group); + + /* see comments in ext4_mb_put_pa() */ + ext4_lock_group(sb, group); + memcpy(data, bitmap, blocksize); + + /* mark all preallocated blks used in in-core bitmap */ + ext4_mb_generate_from_pa(sb, data, group); + WARN_ON_ONCE(!RB_EMPTY_ROOT(&grinfo->bb_free_root)); + ext4_unlock_group(sb, group); + + /* set incore so that the buddy information can be + * generated using this + */ + incore = data; + } + } + folio_mark_uptodate(folio); + +out: + if (bh) { + for (i = 0; i < groups_per_page; i++) + brelse(bh[i]); + if (bh != &bhs) + kfree(bh); + } + return err; +} + +/* + * Lock the buddy and bitmap pages. This make sure other parallel init_group + * on the same buddy page doesn't happen whild holding the buddy page lock. + * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap + * are on the same page e4b->bd_buddy_folio is NULL and return value is 0. + */ +static int ext4_mb_get_buddy_page_lock(struct super_block *sb, + ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp) +{ + struct inode *inode = EXT4_SB(sb)->s_buddy_cache; + int block, pnum, poff; + int blocks_per_page; + struct folio *folio; + + e4b->bd_buddy_folio = NULL; + e4b->bd_bitmap_folio = NULL; + + blocks_per_page = PAGE_SIZE / sb->s_blocksize; + /* + * the buddy cache inode stores the block bitmap + * and buddy information in consecutive blocks. + * So for each group we need two blocks. + */ + block = group * 2; + pnum = block / blocks_per_page; + poff = block % blocks_per_page; + folio = __filemap_get_folio(inode->i_mapping, pnum, + FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp); + if (IS_ERR(folio)) + return PTR_ERR(folio); + BUG_ON(folio->mapping != inode->i_mapping); + e4b->bd_bitmap_folio = folio; + e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize); + + if (blocks_per_page >= 2) { + /* buddy and bitmap are on the same page */ + return 0; + } + + /* blocks_per_page == 1, hence we need another page for the buddy */ + folio = __filemap_get_folio(inode->i_mapping, block + 1, + FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp); + if (IS_ERR(folio)) + return PTR_ERR(folio); + BUG_ON(folio->mapping != inode->i_mapping); + e4b->bd_buddy_folio = folio; + return 0; +} + +static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b) +{ + if (e4b->bd_bitmap_folio) { + folio_unlock(e4b->bd_bitmap_folio); + folio_put(e4b->bd_bitmap_folio); + } + if (e4b->bd_buddy_folio) { + folio_unlock(e4b->bd_buddy_folio); + folio_put(e4b->bd_buddy_folio); + } +} + +/* + * Locking note: This routine calls ext4_mb_init_cache(), which takes the + * block group lock of all groups for this page; do not hold the BG lock when + * calling this routine! + */ +static noinline_for_stack +int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp) +{ + + struct ext4_group_info *this_grp; + struct ext4_buddy e4b; + struct folio *folio; + int ret = 0; + + might_sleep(); + mb_debug(sb, "init group %u\n", group); + this_grp = ext4_get_group_info(sb, group); + if (!this_grp) + return -EFSCORRUPTED; + + /* + * This ensures that we don't reinit the buddy cache + * page which map to the group from which we are already + * allocating. If we are looking at the buddy cache we would + * have taken a reference using ext4_mb_load_buddy and that + * would have pinned buddy page to page cache. + * The call to ext4_mb_get_buddy_page_lock will mark the + * page accessed. + */ + ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp); + if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) { + /* + * somebody initialized the group + * return without doing anything + */ + goto err; + } + + folio = e4b.bd_bitmap_folio; + ret = ext4_mb_init_cache(folio, NULL, gfp); + if (ret) + goto err; + if (!folio_test_uptodate(folio)) { + ret = -EIO; + goto err; + } + + if (e4b.bd_buddy_folio == NULL) { + /* + * If both the bitmap and buddy are in + * the same page we don't need to force + * init the buddy + */ + ret = 0; + goto err; + } + /* init buddy cache */ + folio = e4b.bd_buddy_folio; + ret = ext4_mb_init_cache(folio, e4b.bd_bitmap, gfp); + if (ret) + goto err; + if (!folio_test_uptodate(folio)) { + ret = -EIO; + goto err; + } +err: + ext4_mb_put_buddy_page_lock(&e4b); + return ret; +} + +/* + * Locking note: This routine calls ext4_mb_init_cache(), which takes the + * block group lock of all groups for this page; do not hold the BG lock when + * calling this routine! + */ +static noinline_for_stack int +ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group, + struct ext4_buddy *e4b, gfp_t gfp) +{ + int blocks_per_page; + int block; + int pnum; + int poff; + struct folio *folio; + int ret; + struct ext4_group_info *grp; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct inode *inode = sbi->s_buddy_cache; + + might_sleep(); + mb_debug(sb, "load group %u\n", group); + + blocks_per_page = PAGE_SIZE / sb->s_blocksize; + grp = ext4_get_group_info(sb, group); + if (!grp) + return -EFSCORRUPTED; + + e4b->bd_blkbits = sb->s_blocksize_bits; + e4b->bd_info = grp; + e4b->bd_sb = sb; + e4b->bd_group = group; + e4b->bd_buddy_folio = NULL; + e4b->bd_bitmap_folio = NULL; + + if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) { + /* + * we need full data about the group + * to make a good selection + */ + ret = ext4_mb_init_group(sb, group, gfp); + if (ret) + return ret; + } + + /* + * the buddy cache inode stores the block bitmap + * and buddy information in consecutive blocks. + * So for each group we need two blocks. + */ + block = group * 2; + pnum = block / blocks_per_page; + poff = block % blocks_per_page; + + /* Avoid locking the folio in the fast path ... */ + folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0); + if (IS_ERR(folio) || !folio_test_uptodate(folio)) { + if (!IS_ERR(folio)) + /* + * drop the folio reference and try + * to get the folio with lock. If we + * are not uptodate that implies + * somebody just created the folio but + * is yet to initialize it. So + * wait for it to initialize. + */ + folio_put(folio); + folio = __filemap_get_folio(inode->i_mapping, pnum, + FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp); + if (!IS_ERR(folio)) { + if (WARN_RATELIMIT(folio->mapping != inode->i_mapping, + "ext4: bitmap's mapping != inode->i_mapping\n")) { + /* should never happen */ + folio_unlock(folio); + ret = -EINVAL; + goto err; + } + if (!folio_test_uptodate(folio)) { + ret = ext4_mb_init_cache(folio, NULL, gfp); + if (ret) { + folio_unlock(folio); + goto err; + } + mb_cmp_bitmaps(e4b, folio_address(folio) + + (poff * sb->s_blocksize)); + } + folio_unlock(folio); + } + } + if (IS_ERR(folio)) { + ret = PTR_ERR(folio); + goto err; + } + if (!folio_test_uptodate(folio)) { + ret = -EIO; + goto err; + } + + /* Folios marked accessed already */ + e4b->bd_bitmap_folio = folio; + e4b->bd_bitmap = folio_address(folio) + (poff * sb->s_blocksize); + + block++; + pnum = block / blocks_per_page; + poff = block % blocks_per_page; + + folio = __filemap_get_folio(inode->i_mapping, pnum, FGP_ACCESSED, 0); + if (IS_ERR(folio) || !folio_test_uptodate(folio)) { + if (!IS_ERR(folio)) + folio_put(folio); + folio = __filemap_get_folio(inode->i_mapping, pnum, + FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp); + if (!IS_ERR(folio)) { + if (WARN_RATELIMIT(folio->mapping != inode->i_mapping, + "ext4: buddy bitmap's mapping != inode->i_mapping\n")) { + /* should never happen */ + folio_unlock(folio); + ret = -EINVAL; + goto err; + } + if (!folio_test_uptodate(folio)) { + ret = ext4_mb_init_cache(folio, e4b->bd_bitmap, + gfp); + if (ret) { + folio_unlock(folio); + goto err; + } + } + folio_unlock(folio); + } + } + if (IS_ERR(folio)) { + ret = PTR_ERR(folio); + goto err; + } + if (!folio_test_uptodate(folio)) { + ret = -EIO; + goto err; + } + + /* Folios marked accessed already */ + e4b->bd_buddy_folio = folio; + e4b->bd_buddy = folio_address(folio) + (poff * sb->s_blocksize); + + return 0; + +err: + if (!IS_ERR_OR_NULL(folio)) + folio_put(folio); + if (e4b->bd_bitmap_folio) + folio_put(e4b->bd_bitmap_folio); + + e4b->bd_buddy = NULL; + e4b->bd_bitmap = NULL; + return ret; +} + +static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group, + struct ext4_buddy *e4b) +{ + return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS); +} + +static void ext4_mb_unload_buddy(struct ext4_buddy *e4b) +{ + if (e4b->bd_bitmap_folio) + folio_put(e4b->bd_bitmap_folio); + if (e4b->bd_buddy_folio) + folio_put(e4b->bd_buddy_folio); +} + + +static int mb_find_order_for_block(struct ext4_buddy *e4b, int block) +{ + int order = 1, max; + void *bb; + + BUG_ON(e4b->bd_bitmap == e4b->bd_buddy); + BUG_ON(block >= (1 << (e4b->bd_blkbits + 3))); + + while (order <= e4b->bd_blkbits + 1) { + bb = mb_find_buddy(e4b, order, &max); + if (!mb_test_bit(block >> order, bb)) { + /* this block is part of buddy of order 'order' */ + return order; + } + order++; + } + return 0; +} + +static void mb_clear_bits(void *bm, int cur, int len) +{ + __u32 *addr; + + len = cur + len; + while (cur < len) { + if ((cur & 31) == 0 && (len - cur) >= 32) { + /* fast path: clear whole word at once */ + addr = bm + (cur >> 3); + *addr = 0; + cur += 32; + continue; + } + mb_clear_bit(cur, bm); + cur++; + } +} + +/* clear bits in given range + * will return first found zero bit if any, -1 otherwise + */ +static int mb_test_and_clear_bits(void *bm, int cur, int len) +{ + __u32 *addr; + int zero_bit = -1; + + len = cur + len; + while (cur < len) { + if ((cur & 31) == 0 && (len - cur) >= 32) { + /* fast path: clear whole word at once */ + addr = bm + (cur >> 3); + if (*addr != (__u32)(-1) && zero_bit == -1) + zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0); + *addr = 0; + cur += 32; + continue; + } + if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1) + zero_bit = cur; + cur++; + } + + return zero_bit; +} + +void mb_set_bits(void *bm, int cur, int len) +{ + __u32 *addr; + + len = cur + len; + while (cur < len) { + if ((cur & 31) == 0 && (len - cur) >= 32) { + /* fast path: set whole word at once */ + addr = bm + (cur >> 3); + *addr = 0xffffffff; + cur += 32; + continue; + } + mb_set_bit(cur, bm); + cur++; + } +} + +static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side) +{ + if (mb_test_bit(*bit + side, bitmap)) { + mb_clear_bit(*bit, bitmap); + (*bit) -= side; + return 1; + } + else { + (*bit) += side; + mb_set_bit(*bit, bitmap); + return -1; + } +} + +static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last) +{ + int max; + int order = 1; + void *buddy = mb_find_buddy(e4b, order, &max); + + while (buddy) { + void *buddy2; + + /* Bits in range [first; last] are known to be set since + * corresponding blocks were allocated. Bits in range + * (first; last) will stay set because they form buddies on + * upper layer. We just deal with borders if they don't + * align with upper layer and then go up. + * Releasing entire group is all about clearing + * single bit of highest order buddy. + */ + + /* Example: + * --------------------------------- + * | 1 | 1 | 1 | 1 | + * --------------------------------- + * | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | + * --------------------------------- + * 0 1 2 3 4 5 6 7 + * \_____________________/ + * + * Neither [1] nor [6] is aligned to above layer. + * Left neighbour [0] is free, so mark it busy, + * decrease bb_counters and extend range to + * [0; 6] + * Right neighbour [7] is busy. It can't be coaleasced with [6], so + * mark [6] free, increase bb_counters and shrink range to + * [0; 5]. + * Then shift range to [0; 2], go up and do the same. + */ + + + if (first & 1) + e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1); + if (!(last & 1)) + e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1); + if (first > last) + break; + order++; + + buddy2 = mb_find_buddy(e4b, order, &max); + if (!buddy2) { + mb_clear_bits(buddy, first, last - first + 1); + e4b->bd_info->bb_counters[order - 1] += last - first + 1; + break; + } + first >>= 1; + last >>= 1; + buddy = buddy2; + } +} + +static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b, + int first, int count) +{ + int left_is_free = 0; + int right_is_free = 0; + int block; + int last = first + count - 1; + struct super_block *sb = e4b->bd_sb; + + if (WARN_ON(count == 0)) + return; + BUG_ON(last >= (sb->s_blocksize << 3)); + assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group)); + /* Don't bother if the block group is corrupt. */ + if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) + return; + + mb_check_buddy(e4b); + mb_free_blocks_double(inode, e4b, first, count); + + /* access memory sequentially: check left neighbour, + * clear range and then check right neighbour + */ + if (first != 0) + left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap); + block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count); + if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0]) + right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap); + + if (unlikely(block != -1)) { + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_fsblk_t blocknr; + + /* + * Fastcommit replay can free already freed blocks which + * corrupts allocation info. Regenerate it. + */ + if (sbi->s_mount_state & EXT4_FC_REPLAY) { + mb_regenerate_buddy(e4b); + goto check; + } + + blocknr = ext4_group_first_block_no(sb, e4b->bd_group); + blocknr += EXT4_C2B(sbi, block); + ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + ext4_grp_locked_error(sb, e4b->bd_group, + inode ? inode->i_ino : 0, blocknr, + "freeing already freed block (bit %u); block bitmap corrupt.", + block); + return; + } + + this_cpu_inc(discard_pa_seq); + e4b->bd_info->bb_free += count; + if (first < e4b->bd_info->bb_first_free) + e4b->bd_info->bb_first_free = first; + + /* let's maintain fragments counter */ + if (left_is_free && right_is_free) + e4b->bd_info->bb_fragments--; + else if (!left_is_free && !right_is_free) + e4b->bd_info->bb_fragments++; + + /* buddy[0] == bd_bitmap is a special case, so handle + * it right away and let mb_buddy_mark_free stay free of + * zero order checks. + * Check if neighbours are to be coaleasced, + * adjust bitmap bb_counters and borders appropriately. + */ + if (first & 1) { + first += !left_is_free; + e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1; + } + if (!(last & 1)) { + last -= !right_is_free; + e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1; + } + + if (first <= last) + mb_buddy_mark_free(e4b, first >> 1, last >> 1); + + mb_set_largest_free_order(sb, e4b->bd_info); + mb_update_avg_fragment_size(sb, e4b->bd_info); +check: + mb_check_buddy(e4b); +} + +static int mb_find_extent(struct ext4_buddy *e4b, int block, + int needed, struct ext4_free_extent *ex) +{ + int max, order, next; + void *buddy; + + assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group)); + BUG_ON(ex == NULL); + + buddy = mb_find_buddy(e4b, 0, &max); + BUG_ON(buddy == NULL); + BUG_ON(block >= max); + if (mb_test_bit(block, buddy)) { + ex->fe_len = 0; + ex->fe_start = 0; + ex->fe_group = 0; + return 0; + } + + /* find actual order */ + order = mb_find_order_for_block(e4b, block); + + ex->fe_len = (1 << order) - (block & ((1 << order) - 1)); + ex->fe_start = block; + ex->fe_group = e4b->bd_group; + + block = block >> order; + + while (needed > ex->fe_len && + mb_find_buddy(e4b, order, &max)) { + + if (block + 1 >= max) + break; + + next = (block + 1) * (1 << order); + if (mb_test_bit(next, e4b->bd_bitmap)) + break; + + order = mb_find_order_for_block(e4b, next); + + block = next >> order; + ex->fe_len += 1 << order; + } + + if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) { + /* Should never happen! (but apparently sometimes does?!?) */ + WARN_ON(1); + ext4_grp_locked_error(e4b->bd_sb, e4b->bd_group, 0, 0, + "corruption or bug in mb_find_extent " + "block=%d, order=%d needed=%d ex=%u/%d/%d@%u", + block, order, needed, ex->fe_group, ex->fe_start, + ex->fe_len, ex->fe_logical); + ex->fe_len = 0; + ex->fe_start = 0; + ex->fe_group = 0; + } + return ex->fe_len; +} + +static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex) +{ + int ord; + int mlen = 0; + int max = 0; + int start = ex->fe_start; + int len = ex->fe_len; + unsigned ret = 0; + int len0 = len; + void *buddy; + int ord_start, ord_end; + + BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3)); + BUG_ON(e4b->bd_group != ex->fe_group); + assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group)); + mb_check_buddy(e4b); + mb_mark_used_double(e4b, start, len); + + this_cpu_inc(discard_pa_seq); + e4b->bd_info->bb_free -= len; + if (e4b->bd_info->bb_first_free == start) + e4b->bd_info->bb_first_free += len; + + /* let's maintain fragments counter */ + if (start != 0) + mlen = !mb_test_bit(start - 1, e4b->bd_bitmap); + if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0]) + max = !mb_test_bit(start + len, e4b->bd_bitmap); + if (mlen && max) + e4b->bd_info->bb_fragments++; + else if (!mlen && !max) + e4b->bd_info->bb_fragments--; + + /* let's maintain buddy itself */ + while (len) { + ord = mb_find_order_for_block(e4b, start); + + if (((start >> ord) << ord) == start && len >= (1 << ord)) { + /* the whole chunk may be allocated at once! */ + mlen = 1 << ord; + buddy = mb_find_buddy(e4b, ord, &max); + BUG_ON((start >> ord) >= max); + mb_set_bit(start >> ord, buddy); + e4b->bd_info->bb_counters[ord]--; + start += mlen; + len -= mlen; + BUG_ON(len < 0); + continue; + } + + /* store for history */ + if (ret == 0) + ret = len | (ord << 16); + + BUG_ON(ord <= 0); + buddy = mb_find_buddy(e4b, ord, &max); + mb_set_bit(start >> ord, buddy); + e4b->bd_info->bb_counters[ord]--; + + ord_start = (start >> ord) << ord; + ord_end = ord_start + (1 << ord); + /* first chunk */ + if (start > ord_start) + ext4_mb_mark_free_simple(e4b->bd_sb, e4b->bd_buddy, + ord_start, start - ord_start, + e4b->bd_info); + + /* last chunk */ + if (start + len < ord_end) { + ext4_mb_mark_free_simple(e4b->bd_sb, e4b->bd_buddy, + start + len, + ord_end - (start + len), + e4b->bd_info); + break; + } + len = start + len - ord_end; + start = ord_end; + } + mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info); + + mb_update_avg_fragment_size(e4b->bd_sb, e4b->bd_info); + mb_set_bits(e4b->bd_bitmap, ex->fe_start, len0); + mb_check_buddy(e4b); + + return ret; +} + +/* + * Must be called under group lock! + */ +static void ext4_mb_use_best_found(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + int ret; + + BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group); + BUG_ON(ac->ac_status == AC_STATUS_FOUND); + + ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len); + ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical; + ret = mb_mark_used(e4b, &ac->ac_b_ex); + + /* preallocation can change ac_b_ex, thus we store actually + * allocated blocks for history */ + ac->ac_f_ex = ac->ac_b_ex; + + ac->ac_status = AC_STATUS_FOUND; + ac->ac_tail = ret & 0xffff; + ac->ac_buddy = ret >> 16; + + /* + * take the page reference. We want the page to be pinned + * so that we don't get a ext4_mb_init_cache_call for this + * group until we update the bitmap. That would mean we + * double allocate blocks. The reference is dropped + * in ext4_mb_release_context + */ + ac->ac_bitmap_folio = e4b->bd_bitmap_folio; + folio_get(ac->ac_bitmap_folio); + ac->ac_buddy_folio = e4b->bd_buddy_folio; + folio_get(ac->ac_buddy_folio); + /* store last allocated for subsequent stream allocation */ + if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) { + int hash = ac->ac_inode->i_ino % sbi->s_mb_nr_global_goals; + + WRITE_ONCE(sbi->s_mb_last_groups[hash], ac->ac_f_ex.fe_group); + } + + /* + * As we've just preallocated more space than + * user requested originally, we store allocated + * space in a special descriptor. + */ + if (ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len) + ext4_mb_new_preallocation(ac); + +} + +static void ext4_mb_check_limits(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b, + int finish_group) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + struct ext4_free_extent *bex = &ac->ac_b_ex; + struct ext4_free_extent *gex = &ac->ac_g_ex; + + if (ac->ac_status == AC_STATUS_FOUND) + return; + /* + * We don't want to scan for a whole year + */ + if (ac->ac_found > sbi->s_mb_max_to_scan && + !(ac->ac_flags & EXT4_MB_HINT_FIRST)) { + ac->ac_status = AC_STATUS_BREAK; + return; + } + + /* + * Haven't found good chunk so far, let's continue + */ + if (bex->fe_len < gex->fe_len) + return; + + if (finish_group || ac->ac_found > sbi->s_mb_min_to_scan) + ext4_mb_use_best_found(ac, e4b); +} + +/* + * The routine checks whether found extent is good enough. If it is, + * then the extent gets marked used and flag is set to the context + * to stop scanning. Otherwise, the extent is compared with the + * previous found extent and if new one is better, then it's stored + * in the context. Later, the best found extent will be used, if + * mballoc can't find good enough extent. + * + * The algorithm used is roughly as follows: + * + * * If free extent found is exactly as big as goal, then + * stop the scan and use it immediately + * + * * If free extent found is smaller than goal, then keep retrying + * upto a max of sbi->s_mb_max_to_scan times (default 200). After + * that stop scanning and use whatever we have. + * + * * If free extent found is bigger than goal, then keep retrying + * upto a max of sbi->s_mb_min_to_scan times (default 10) before + * stopping the scan and using the extent. + * + * + * FIXME: real allocation policy is to be designed yet! + */ +static void ext4_mb_measure_extent(struct ext4_allocation_context *ac, + struct ext4_free_extent *ex, + struct ext4_buddy *e4b) +{ + struct ext4_free_extent *bex = &ac->ac_b_ex; + struct ext4_free_extent *gex = &ac->ac_g_ex; + + BUG_ON(ex->fe_len <= 0); + BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb)); + BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb)); + BUG_ON(ac->ac_status != AC_STATUS_CONTINUE); + + ac->ac_found++; + ac->ac_cX_found[ac->ac_criteria]++; + + /* + * The special case - take what you catch first + */ + if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) { + *bex = *ex; + ext4_mb_use_best_found(ac, e4b); + return; + } + + /* + * Let's check whether the chuck is good enough + */ + if (ex->fe_len == gex->fe_len) { + *bex = *ex; + ext4_mb_use_best_found(ac, e4b); + return; + } + + /* + * If this is first found extent, just store it in the context + */ + if (bex->fe_len == 0) { + *bex = *ex; + return; + } + + /* + * If new found extent is better, store it in the context + */ + if (bex->fe_len < gex->fe_len) { + /* if the request isn't satisfied, any found extent + * larger than previous best one is better */ + if (ex->fe_len > bex->fe_len) + *bex = *ex; + } else if (ex->fe_len > gex->fe_len) { + /* if the request is satisfied, then we try to find + * an extent that still satisfy the request, but is + * smaller than previous one */ + if (ex->fe_len < bex->fe_len) + *bex = *ex; + } + + ext4_mb_check_limits(ac, e4b, 0); +} + +static noinline_for_stack +void ext4_mb_try_best_found(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct ext4_free_extent ex = ac->ac_b_ex; + ext4_group_t group = ex.fe_group; + int max; + int err; + + BUG_ON(ex.fe_len <= 0); + err = ext4_mb_load_buddy(ac->ac_sb, group, e4b); + if (err) + return; + + ext4_lock_group(ac->ac_sb, group); + if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) + goto out; + + max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex); + + if (max > 0) { + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + } + +out: + ext4_unlock_group(ac->ac_sb, group); + ext4_mb_unload_buddy(e4b); +} + +static noinline_for_stack +int ext4_mb_find_by_goal(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + ext4_group_t group = ac->ac_g_ex.fe_group; + int max; + int err; + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); + struct ext4_free_extent ex; + + if (!grp) + return -EFSCORRUPTED; + if (!(ac->ac_flags & (EXT4_MB_HINT_TRY_GOAL | EXT4_MB_HINT_GOAL_ONLY))) + return 0; + if (grp->bb_free == 0) + return 0; + + err = ext4_mb_load_buddy(ac->ac_sb, group, e4b); + if (err) + return err; + + ext4_lock_group(ac->ac_sb, group); + if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) + goto out; + + max = mb_find_extent(e4b, ac->ac_g_ex.fe_start, + ac->ac_g_ex.fe_len, &ex); + ex.fe_logical = 0xDEADFA11; /* debug value */ + + if (max >= ac->ac_g_ex.fe_len && + ac->ac_g_ex.fe_len == EXT4_NUM_B2C(sbi, sbi->s_stripe)) { + ext4_fsblk_t start; + + start = ext4_grp_offs_to_block(ac->ac_sb, &ex); + /* use do_div to get remainder (would be 64-bit modulo) */ + if (do_div(start, sbi->s_stripe) == 0) { + ac->ac_found++; + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + } + } else if (max >= ac->ac_g_ex.fe_len) { + BUG_ON(ex.fe_len <= 0); + BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group); + BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start); + ac->ac_found++; + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + } else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) { + /* Sometimes, caller may want to merge even small + * number of blocks to an existing extent */ + BUG_ON(ex.fe_len <= 0); + BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group); + BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start); + ac->ac_found++; + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + } +out: + ext4_unlock_group(ac->ac_sb, group); + ext4_mb_unload_buddy(e4b); + + return 0; +} + +/* + * The routine scans buddy structures (not bitmap!) from given order + * to max order and tries to find big enough chunk to satisfy the req + */ +static noinline_for_stack +void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_group_info *grp = e4b->bd_info; + void *buddy; + int i; + int k; + int max; + + BUG_ON(ac->ac_2order <= 0); + for (i = ac->ac_2order; i < MB_NUM_ORDERS(sb); i++) { + if (grp->bb_counters[i] == 0) + continue; + + buddy = mb_find_buddy(e4b, i, &max); + if (WARN_RATELIMIT(buddy == NULL, + "ext4: mb_simple_scan_group: mb_find_buddy failed, (%d)\n", i)) + continue; + + k = mb_find_next_zero_bit(buddy, max, 0); + if (k >= max) { + ext4_mark_group_bitmap_corrupted(ac->ac_sb, + e4b->bd_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + ext4_grp_locked_error(ac->ac_sb, e4b->bd_group, 0, 0, + "%d free clusters of order %d. But found 0", + grp->bb_counters[i], i); + break; + } + ac->ac_found++; + ac->ac_cX_found[ac->ac_criteria]++; + + ac->ac_b_ex.fe_len = 1 << i; + ac->ac_b_ex.fe_start = k << i; + ac->ac_b_ex.fe_group = e4b->bd_group; + + ext4_mb_use_best_found(ac, e4b); + + BUG_ON(ac->ac_f_ex.fe_len != ac->ac_g_ex.fe_len); + + if (EXT4_SB(sb)->s_mb_stats) + atomic_inc(&EXT4_SB(sb)->s_bal_2orders); + + break; + } +} + +/* + * The routine scans the group and measures all found extents. + * In order to optimize scanning, caller must pass number of + * free blocks in the group, so the routine can know upper limit. + */ +static noinline_for_stack +void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct super_block *sb = ac->ac_sb; + void *bitmap = e4b->bd_bitmap; + struct ext4_free_extent ex; + int i, j, freelen; + int free; + + free = e4b->bd_info->bb_free; + if (WARN_ON(free <= 0)) + return; + + i = e4b->bd_info->bb_first_free; + + while (free && ac->ac_status == AC_STATUS_CONTINUE) { + i = mb_find_next_zero_bit(bitmap, + EXT4_CLUSTERS_PER_GROUP(sb), i); + if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) { + /* + * IF we have corrupt bitmap, we won't find any + * free blocks even though group info says we + * have free blocks + */ + ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + ext4_grp_locked_error(sb, e4b->bd_group, 0, 0, + "%d free clusters as per " + "group info. But bitmap says 0", + free); + break; + } + + if (!ext4_mb_cr_expensive(ac->ac_criteria)) { + /* + * In CR_GOAL_LEN_FAST and CR_BEST_AVAIL_LEN, we are + * sure that this group will have a large enough + * continuous free extent, so skip over the smaller free + * extents + */ + j = mb_find_next_bit(bitmap, + EXT4_CLUSTERS_PER_GROUP(sb), i); + freelen = j - i; + + if (freelen < ac->ac_g_ex.fe_len) { + i = j; + free -= freelen; + continue; + } + } + + mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex); + if (WARN_ON(ex.fe_len <= 0)) + break; + if (free < ex.fe_len) { + ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, + EXT4_GROUP_INFO_BBITMAP_CORRUPT); + ext4_grp_locked_error(sb, e4b->bd_group, 0, 0, + "%d free clusters as per " + "group info. But got %d blocks", + free, ex.fe_len); + /* + * The number of free blocks differs. This mostly + * indicate that the bitmap is corrupt. So exit + * without claiming the space. + */ + break; + } + ex.fe_logical = 0xDEADC0DE; /* debug value */ + ext4_mb_measure_extent(ac, &ex, e4b); + + i += ex.fe_len; + free -= ex.fe_len; + } + + ext4_mb_check_limits(ac, e4b, 1); +} + +/* + * This is a special case for storages like raid5 + * we try to find stripe-aligned chunks for stripe-size-multiple requests + */ +static noinline_for_stack +void ext4_mb_scan_aligned(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + void *bitmap = e4b->bd_bitmap; + struct ext4_free_extent ex; + ext4_fsblk_t first_group_block; + ext4_fsblk_t a; + ext4_grpblk_t i, stripe; + int max; + + BUG_ON(sbi->s_stripe == 0); + + /* find first stripe-aligned block in group */ + first_group_block = ext4_group_first_block_no(sb, e4b->bd_group); + + a = first_group_block + sbi->s_stripe - 1; + do_div(a, sbi->s_stripe); + i = (a * sbi->s_stripe) - first_group_block; + + stripe = EXT4_NUM_B2C(sbi, sbi->s_stripe); + i = EXT4_B2C(sbi, i); + while (i < EXT4_CLUSTERS_PER_GROUP(sb)) { + if (!mb_test_bit(i, bitmap)) { + max = mb_find_extent(e4b, i, stripe, &ex); + if (max >= stripe) { + ac->ac_found++; + ac->ac_cX_found[ac->ac_criteria]++; + ex.fe_logical = 0xDEADF00D; /* debug value */ + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + break; + } + } + i += stripe; + } +} + +static void __ext4_mb_scan_group(struct ext4_allocation_context *ac) +{ + bool is_stripe_aligned; + struct ext4_sb_info *sbi; + enum criteria cr = ac->ac_criteria; + + ac->ac_groups_scanned++; + if (cr == CR_POWER2_ALIGNED) + return ext4_mb_simple_scan_group(ac, ac->ac_e4b); + + sbi = EXT4_SB(ac->ac_sb); + is_stripe_aligned = false; + if ((sbi->s_stripe >= sbi->s_cluster_ratio) && + !(ac->ac_g_ex.fe_len % EXT4_NUM_B2C(sbi, sbi->s_stripe))) + is_stripe_aligned = true; + + if ((cr == CR_GOAL_LEN_FAST || cr == CR_BEST_AVAIL_LEN) && + is_stripe_aligned) + ext4_mb_scan_aligned(ac, ac->ac_e4b); + + if (ac->ac_status == AC_STATUS_CONTINUE) + ext4_mb_complex_scan_group(ac, ac->ac_e4b); +} + +/* + * This is also called BEFORE we load the buddy bitmap. + * Returns either 1 or 0 indicating that the group is either suitable + * for the allocation or not. + */ +static bool ext4_mb_good_group(struct ext4_allocation_context *ac, + ext4_group_t group, enum criteria cr) +{ + ext4_grpblk_t free, fragments; + int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb)); + struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); + + BUG_ON(cr < CR_POWER2_ALIGNED || cr >= EXT4_MB_NUM_CRS); + + if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) + return false; + + free = grp->bb_free; + if (free == 0) + return false; + + fragments = grp->bb_fragments; + if (fragments == 0) + return false; + + switch (cr) { + case CR_POWER2_ALIGNED: + BUG_ON(ac->ac_2order == 0); + + /* Avoid using the first bg of a flexgroup for data files */ + if ((ac->ac_flags & EXT4_MB_HINT_DATA) && + (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) && + ((group % flex_size) == 0)) + return false; + + if (free < ac->ac_g_ex.fe_len) + return false; + + if (ac->ac_2order >= MB_NUM_ORDERS(ac->ac_sb)) + return true; + + if (grp->bb_largest_free_order < ac->ac_2order) + return false; + + return true; + case CR_GOAL_LEN_FAST: + case CR_BEST_AVAIL_LEN: + if ((free / fragments) >= ac->ac_g_ex.fe_len) + return true; + break; + case CR_GOAL_LEN_SLOW: + if (free >= ac->ac_g_ex.fe_len) + return true; + break; + case CR_ANY_FREE: + return true; + default: + BUG(); + } + + return false; +} + +/* + * This could return negative error code if something goes wrong + * during ext4_mb_init_group(). This should not be called with + * ext4_lock_group() held. + * + * Note: because we are conditionally operating with the group lock in + * the EXT4_MB_STRICT_CHECK case, we need to fake out sparse in this + * function using __acquire and __release. This means we need to be + * super careful before messing with the error path handling via "goto + * out"! + */ +static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac, + ext4_group_t group, enum criteria cr) +{ + struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); + struct super_block *sb = ac->ac_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + bool should_lock = ac->ac_flags & EXT4_MB_STRICT_CHECK; + ext4_grpblk_t free; + int ret = 0; + + if (!grp) + return -EFSCORRUPTED; + if (sbi->s_mb_stats) + atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]); + if (should_lock) { + ext4_lock_group(sb, group); + __release(ext4_group_lock_ptr(sb, group)); + } + free = grp->bb_free; + if (free == 0) + goto out; + /* + * In all criterias except CR_ANY_FREE we try to avoid groups that + * can't possibly satisfy the full goal request due to insufficient + * free blocks. + */ + if (cr < CR_ANY_FREE && free < ac->ac_g_ex.fe_len) + goto out; + if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) + goto out; + if (should_lock) { + __acquire(ext4_group_lock_ptr(sb, group)); + ext4_unlock_group(sb, group); + } + + /* We only do this if the grp has never been initialized */ + if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) { + struct ext4_group_desc *gdp = + ext4_get_group_desc(sb, group, NULL); + int ret; + + /* + * CR_POWER2_ALIGNED/CR_GOAL_LEN_FAST is a very optimistic + * search to find large good chunks almost for free. If buddy + * data is not ready, then this optimization makes no sense. But + * we never skip the first block group in a flex_bg, since this + * gets used for metadata block allocation, and we want to make + * sure we locate metadata blocks in the first block group in + * the flex_bg if possible. + */ + if (!ext4_mb_cr_expensive(cr) && + (!sbi->s_log_groups_per_flex || + ((group & ((1 << sbi->s_log_groups_per_flex) - 1)) != 0)) && + !(ext4_has_group_desc_csum(sb) && + (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) + return 0; + ret = ext4_mb_init_group(sb, group, GFP_NOFS); + if (ret) + return ret; + } + + if (should_lock) { + ext4_lock_group(sb, group); + __release(ext4_group_lock_ptr(sb, group)); + } + ret = ext4_mb_good_group(ac, group, cr); +out: + if (should_lock) { + __acquire(ext4_group_lock_ptr(sb, group)); + ext4_unlock_group(sb, group); + } + return ret; +} + +/* + * Start prefetching @nr block bitmaps starting at @group. + * Return the next group which needs to be prefetched. + */ +ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group, + unsigned int nr, int *cnt) +{ + ext4_group_t ngroups = ext4_get_groups_count(sb); + struct buffer_head *bh; + struct blk_plug plug; + + blk_start_plug(&plug); + while (nr-- > 0) { + struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, + NULL); + struct ext4_group_info *grp = ext4_get_group_info(sb, group); + + /* + * Prefetch block groups with free blocks; but don't + * bother if it is marked uninitialized on disk, since + * it won't require I/O to read. Also only try to + * prefetch once, so we avoid getblk() call, which can + * be expensive. + */ + if (gdp && grp && !EXT4_MB_GRP_TEST_AND_SET_READ(grp) && + EXT4_MB_GRP_NEED_INIT(grp) && + ext4_free_group_clusters(sb, gdp) > 0 ) { + bh = ext4_read_block_bitmap_nowait(sb, group, true); + if (bh && !IS_ERR(bh)) { + if (!buffer_uptodate(bh) && cnt) + (*cnt)++; + brelse(bh); + } + } + if (++group >= ngroups) + group = 0; + } + blk_finish_plug(&plug); + return group; +} + +/* + * Batch reads of the block allocation bitmaps to get + * multiple READs in flight; limit prefetching at inexpensive + * CR, otherwise mballoc can spend a lot of time loading + * imperfect groups + */ +static void ext4_mb_might_prefetch(struct ext4_allocation_context *ac, + ext4_group_t group) +{ + struct ext4_sb_info *sbi; + + if (ac->ac_prefetch_grp != group) + return; + + sbi = EXT4_SB(ac->ac_sb); + if (ext4_mb_cr_expensive(ac->ac_criteria) || + ac->ac_prefetch_ios < sbi->s_mb_prefetch_limit) { + unsigned int nr = sbi->s_mb_prefetch; + + if (ext4_has_feature_flex_bg(ac->ac_sb)) { + nr = 1 << sbi->s_log_groups_per_flex; + nr -= group & (nr - 1); + nr = umin(nr, sbi->s_mb_prefetch); + } + + ac->ac_prefetch_nr = nr; + ac->ac_prefetch_grp = ext4_mb_prefetch(ac->ac_sb, group, nr, + &ac->ac_prefetch_ios); + } +} + +/* + * Prefetching reads the block bitmap into the buffer cache; but we + * need to make sure that the buddy bitmap in the page cache has been + * initialized. Note that ext4_mb_init_group() will block if the I/O + * is not yet completed, or indeed if it was not initiated by + * ext4_mb_prefetch did not start the I/O. + * + * TODO: We should actually kick off the buddy bitmap setup in a work + * queue when the buffer I/O is completed, so that we don't block + * waiting for the block allocation bitmap read to finish when + * ext4_mb_prefetch_fini is called from ext4_mb_regular_allocator(). + */ +void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group, + unsigned int nr) +{ + struct ext4_group_desc *gdp; + struct ext4_group_info *grp; + + while (nr-- > 0) { + if (!group) + group = ext4_get_groups_count(sb); + group--; + gdp = ext4_get_group_desc(sb, group, NULL); + grp = ext4_get_group_info(sb, group); + + if (grp && gdp && EXT4_MB_GRP_NEED_INIT(grp) && + ext4_free_group_clusters(sb, gdp) > 0) { + if (ext4_mb_init_group(sb, group, GFP_NOFS)) + break; + } + } +} + +static int ext4_mb_scan_group(struct ext4_allocation_context *ac, + ext4_group_t group) +{ + int ret; + struct super_block *sb = ac->ac_sb; + enum criteria cr = ac->ac_criteria; + + ext4_mb_might_prefetch(ac, group); + + /* prevent unnecessary buddy loading. */ + if (cr < CR_ANY_FREE && spin_is_locked(ext4_group_lock_ptr(sb, group))) + return 0; + + /* This now checks without needing the buddy page */ + ret = ext4_mb_good_group_nolock(ac, group, cr); + if (ret <= 0) { + if (!ac->ac_first_err) + ac->ac_first_err = ret; + return 0; + } + + ret = ext4_mb_load_buddy(sb, group, ac->ac_e4b); + if (ret) + return ret; + + /* skip busy group */ + if (cr >= CR_ANY_FREE) + ext4_lock_group(sb, group); + else if (!ext4_try_lock_group(sb, group)) + goto out_unload; + + /* We need to check again after locking the block group. */ + if (unlikely(!ext4_mb_good_group(ac, group, cr))) + goto out_unlock; + + __ext4_mb_scan_group(ac); + +out_unlock: + ext4_unlock_group(sb, group); +out_unload: + ext4_mb_unload_buddy(ac->ac_e4b); + return ret; +} + +static noinline_for_stack int +ext4_mb_regular_allocator(struct ext4_allocation_context *ac) +{ + ext4_group_t i; + int err = 0; + struct super_block *sb = ac->ac_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_buddy e4b; + + BUG_ON(ac->ac_status == AC_STATUS_FOUND); + + /* first, try the goal */ + err = ext4_mb_find_by_goal(ac, &e4b); + if (err || ac->ac_status == AC_STATUS_FOUND) + goto out; + + if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) + goto out; + + /* + * ac->ac_2order is set only if the fe_len is a power of 2 + * if ac->ac_2order is set we also set criteria to CR_POWER2_ALIGNED + * so that we try exact allocation using buddy. + */ + i = fls(ac->ac_g_ex.fe_len); + ac->ac_2order = 0; + /* + * We search using buddy data only if the order of the request + * is greater than equal to the sbi_s_mb_order2_reqs + * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req + * We also support searching for power-of-two requests only for + * requests upto maximum buddy size we have constructed. + */ + if (i >= sbi->s_mb_order2_reqs && i <= MB_NUM_ORDERS(sb)) { + if (is_power_of_2(ac->ac_g_ex.fe_len)) + ac->ac_2order = array_index_nospec(i - 1, + MB_NUM_ORDERS(sb)); + } + + /* if stream allocation is enabled, use global goal */ + if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) { + int hash = ac->ac_inode->i_ino % sbi->s_mb_nr_global_goals; + + ac->ac_g_ex.fe_group = READ_ONCE(sbi->s_mb_last_groups[hash]); + ac->ac_g_ex.fe_start = -1; + ac->ac_flags &= ~EXT4_MB_HINT_TRY_GOAL; + } + + /* + * Let's just scan groups to find more-less suitable blocks We + * start with CR_GOAL_LEN_FAST, unless it is power of 2 + * aligned, in which case let's do that faster approach first. + */ + ac->ac_criteria = CR_GOAL_LEN_FAST; + if (ac->ac_2order) + ac->ac_criteria = CR_POWER2_ALIGNED; + + ac->ac_e4b = &e4b; + ac->ac_prefetch_ios = 0; + ac->ac_first_err = 0; +repeat: + while (ac->ac_criteria < EXT4_MB_NUM_CRS) { + err = ext4_mb_scan_groups(ac); + if (err) + goto out; + + if (ac->ac_status != AC_STATUS_CONTINUE) + break; + } + + if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND && + !(ac->ac_flags & EXT4_MB_HINT_FIRST)) { + /* + * We've been searching too long. Let's try to allocate + * the best chunk we've found so far + */ + ext4_mb_try_best_found(ac, &e4b); + if (ac->ac_status != AC_STATUS_FOUND) { + int lost; + + /* + * Someone more lucky has already allocated it. + * The only thing we can do is just take first + * found block(s) + */ + lost = atomic_inc_return(&sbi->s_mb_lost_chunks); + mb_debug(sb, "lost chunk, group: %u, start: %d, len: %d, lost: %d\n", + ac->ac_b_ex.fe_group, ac->ac_b_ex.fe_start, + ac->ac_b_ex.fe_len, lost); + + ac->ac_b_ex.fe_group = 0; + ac->ac_b_ex.fe_start = 0; + ac->ac_b_ex.fe_len = 0; + ac->ac_status = AC_STATUS_CONTINUE; + ac->ac_flags |= EXT4_MB_HINT_FIRST; + ac->ac_criteria = CR_ANY_FREE; + goto repeat; + } + } + + if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND) { + atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]); + if (ac->ac_flags & EXT4_MB_STREAM_ALLOC && + ac->ac_b_ex.fe_group == ac->ac_g_ex.fe_group) + atomic_inc(&sbi->s_bal_stream_goals); + } +out: + if (!err && ac->ac_status != AC_STATUS_FOUND && ac->ac_first_err) + err = ac->ac_first_err; + + mb_debug(sb, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n", + ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status, + ac->ac_flags, ac->ac_criteria, err); + + if (ac->ac_prefetch_nr) + ext4_mb_prefetch_fini(sb, ac->ac_prefetch_grp, ac->ac_prefetch_nr); + + return err; +} + +static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos) +{ + struct super_block *sb = pde_data(file_inode(seq->file)); + ext4_group_t group; + + if (*pos < 0 || *pos >= ext4_get_groups_count(sb)) + return NULL; + group = *pos + 1; + return (void *) ((unsigned long) group); +} + +static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct super_block *sb = pde_data(file_inode(seq->file)); + ext4_group_t group; + + ++*pos; + if (*pos < 0 || *pos >= ext4_get_groups_count(sb)) + return NULL; + group = *pos + 1; + return (void *) ((unsigned long) group); +} + +static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v) +{ + struct super_block *sb = pde_data(file_inode(seq->file)); + ext4_group_t group = (ext4_group_t) ((unsigned long) v); + int i, err; + char nbuf[16]; + struct ext4_buddy e4b; + struct ext4_group_info *grinfo; + unsigned char blocksize_bits = min_t(unsigned char, + sb->s_blocksize_bits, + EXT4_MAX_BLOCK_LOG_SIZE); + DEFINE_RAW_FLEX(struct ext4_group_info, sg, bb_counters, + EXT4_MAX_BLOCK_LOG_SIZE + 2); + + group--; + if (group == 0) + seq_puts(seq, "#group: free frags first [" + " 2^0 2^1 2^2 2^3 2^4 2^5 2^6 " + " 2^7 2^8 2^9 2^10 2^11 2^12 2^13 ]\n"); + + i = (blocksize_bits + 2) * sizeof(sg->bb_counters[0]) + + sizeof(struct ext4_group_info); + + grinfo = ext4_get_group_info(sb, group); + if (!grinfo) + return 0; + /* Load the group info in memory only if not already loaded. */ + if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) { + err = ext4_mb_load_buddy(sb, group, &e4b); + if (err) { + seq_printf(seq, "#%-5u: %s\n", group, ext4_decode_error(NULL, err, nbuf)); + return 0; + } + ext4_mb_unload_buddy(&e4b); + } + + /* + * We care only about free space counters in the group info and + * these are safe to access even after the buddy has been unloaded + */ + memcpy(sg, grinfo, i); + seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg->bb_free, + sg->bb_fragments, sg->bb_first_free); + for (i = 0; i <= 13; i++) + seq_printf(seq, " %-5u", i <= blocksize_bits + 1 ? + sg->bb_counters[i] : 0); + seq_puts(seq, " ]"); + if (EXT4_MB_GRP_BBITMAP_CORRUPT(sg)) + seq_puts(seq, " Block bitmap corrupted!"); + seq_putc(seq, '\n'); + return 0; +} + +static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v) +{ +} + +const struct seq_operations ext4_mb_seq_groups_ops = { + .start = ext4_mb_seq_groups_start, + .next = ext4_mb_seq_groups_next, + .stop = ext4_mb_seq_groups_stop, + .show = ext4_mb_seq_groups_show, +}; + +int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset) +{ + struct super_block *sb = seq->private; + struct ext4_sb_info *sbi = EXT4_SB(sb); + + seq_puts(seq, "mballoc:\n"); + if (!sbi->s_mb_stats) { + seq_puts(seq, "\tmb stats collection turned off.\n"); + seq_puts( + seq, + "\tTo enable, please write \"1\" to sysfs file mb_stats.\n"); + return 0; + } + seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs)); + seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success)); + + seq_printf(seq, "\tgroups_scanned: %u\n", + atomic_read(&sbi->s_bal_groups_scanned)); + + /* CR_POWER2_ALIGNED stats */ + seq_puts(seq, "\tcr_p2_aligned_stats:\n"); + seq_printf(seq, "\t\thits: %llu\n", + atomic64_read(&sbi->s_bal_cX_hits[CR_POWER2_ALIGNED])); + seq_printf( + seq, "\t\tgroups_considered: %llu\n", + atomic64_read( + &sbi->s_bal_cX_groups_considered[CR_POWER2_ALIGNED])); + seq_printf(seq, "\t\textents_scanned: %u\n", + atomic_read(&sbi->s_bal_cX_ex_scanned[CR_POWER2_ALIGNED])); + seq_printf(seq, "\t\tuseless_loops: %llu\n", + atomic64_read(&sbi->s_bal_cX_failed[CR_POWER2_ALIGNED])); + + /* CR_GOAL_LEN_FAST stats */ + seq_puts(seq, "\tcr_goal_fast_stats:\n"); + seq_printf(seq, "\t\thits: %llu\n", + atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_FAST])); + seq_printf(seq, "\t\tgroups_considered: %llu\n", + atomic64_read( + &sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_FAST])); + seq_printf(seq, "\t\textents_scanned: %u\n", + atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_FAST])); + seq_printf(seq, "\t\tuseless_loops: %llu\n", + atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_FAST])); + + /* CR_BEST_AVAIL_LEN stats */ + seq_puts(seq, "\tcr_best_avail_stats:\n"); + seq_printf(seq, "\t\thits: %llu\n", + atomic64_read(&sbi->s_bal_cX_hits[CR_BEST_AVAIL_LEN])); + seq_printf( + seq, "\t\tgroups_considered: %llu\n", + atomic64_read( + &sbi->s_bal_cX_groups_considered[CR_BEST_AVAIL_LEN])); + seq_printf(seq, "\t\textents_scanned: %u\n", + atomic_read(&sbi->s_bal_cX_ex_scanned[CR_BEST_AVAIL_LEN])); + seq_printf(seq, "\t\tuseless_loops: %llu\n", + atomic64_read(&sbi->s_bal_cX_failed[CR_BEST_AVAIL_LEN])); + + /* CR_GOAL_LEN_SLOW stats */ + seq_puts(seq, "\tcr_goal_slow_stats:\n"); + seq_printf(seq, "\t\thits: %llu\n", + atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_SLOW])); + seq_printf(seq, "\t\tgroups_considered: %llu\n", + atomic64_read( + &sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_SLOW])); + seq_printf(seq, "\t\textents_scanned: %u\n", + atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_SLOW])); + seq_printf(seq, "\t\tuseless_loops: %llu\n", + atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_SLOW])); + + /* CR_ANY_FREE stats */ + seq_puts(seq, "\tcr_any_free_stats:\n"); + seq_printf(seq, "\t\thits: %llu\n", + atomic64_read(&sbi->s_bal_cX_hits[CR_ANY_FREE])); + seq_printf( + seq, "\t\tgroups_considered: %llu\n", + atomic64_read(&sbi->s_bal_cX_groups_considered[CR_ANY_FREE])); + seq_printf(seq, "\t\textents_scanned: %u\n", + atomic_read(&sbi->s_bal_cX_ex_scanned[CR_ANY_FREE])); + seq_printf(seq, "\t\tuseless_loops: %llu\n", + atomic64_read(&sbi->s_bal_cX_failed[CR_ANY_FREE])); + + /* Aggregates */ + seq_printf(seq, "\textents_scanned: %u\n", + atomic_read(&sbi->s_bal_ex_scanned)); + seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals)); + seq_printf(seq, "\t\tstream_goal_hits: %u\n", + atomic_read(&sbi->s_bal_stream_goals)); + seq_printf(seq, "\t\tlen_goal_hits: %u\n", + atomic_read(&sbi->s_bal_len_goals)); + seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders)); + seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks)); + seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks)); + seq_printf(seq, "\tbuddies_generated: %u/%u\n", + atomic_read(&sbi->s_mb_buddies_generated), + ext4_get_groups_count(sb)); + seq_printf(seq, "\tbuddies_time_used: %llu\n", + atomic64_read(&sbi->s_mb_generation_time)); + seq_printf(seq, "\tpreallocated: %u\n", + atomic_read(&sbi->s_mb_preallocated)); + seq_printf(seq, "\tdiscarded: %u\n", atomic_read(&sbi->s_mb_discarded)); + return 0; +} + +static void *ext4_mb_seq_structs_summary_start(struct seq_file *seq, loff_t *pos) +{ + struct super_block *sb = pde_data(file_inode(seq->file)); + unsigned long position; + + if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb)) + return NULL; + position = *pos + 1; + return (void *) ((unsigned long) position); +} + +static void *ext4_mb_seq_structs_summary_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct super_block *sb = pde_data(file_inode(seq->file)); + unsigned long position; + + ++*pos; + if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb)) + return NULL; + position = *pos + 1; + return (void *) ((unsigned long) position); +} + +static int ext4_mb_seq_structs_summary_show(struct seq_file *seq, void *v) +{ + struct super_block *sb = pde_data(file_inode(seq->file)); + struct ext4_sb_info *sbi = EXT4_SB(sb); + unsigned long position = ((unsigned long) v); + struct ext4_group_info *grp; + unsigned int count; + unsigned long idx; + + position--; + if (position >= MB_NUM_ORDERS(sb)) { + position -= MB_NUM_ORDERS(sb); + if (position == 0) + seq_puts(seq, "avg_fragment_size_lists:\n"); + + count = 0; + xa_for_each(&sbi->s_mb_avg_fragment_size[position], idx, grp) + count++; + seq_printf(seq, "\tlist_order_%u_groups: %u\n", + (unsigned int)position, count); + return 0; + } + + if (position == 0) { + seq_printf(seq, "optimize_scan: %d\n", + test_opt2(sb, MB_OPTIMIZE_SCAN) ? 1 : 0); + seq_puts(seq, "max_free_order_lists:\n"); + } + count = 0; + xa_for_each(&sbi->s_mb_largest_free_orders[position], idx, grp) + count++; + seq_printf(seq, "\tlist_order_%u_groups: %u\n", + (unsigned int)position, count); + + return 0; +} + +static void ext4_mb_seq_structs_summary_stop(struct seq_file *seq, void *v) +{ +} + +const struct seq_operations ext4_mb_seq_structs_summary_ops = { + .start = ext4_mb_seq_structs_summary_start, + .next = ext4_mb_seq_structs_summary_next, + .stop = ext4_mb_seq_structs_summary_stop, + .show = ext4_mb_seq_structs_summary_show, +}; + +static struct kmem_cache *get_groupinfo_cache(int blocksize_bits) +{ + int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE; + struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index]; + + BUG_ON(!cachep); + return cachep; +} + +/* + * Allocate the top-level s_group_info array for the specified number + * of groups + */ +int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + unsigned size; + struct ext4_group_info ***old_groupinfo, ***new_groupinfo; + + size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >> + EXT4_DESC_PER_BLOCK_BITS(sb); + if (size <= sbi->s_group_info_size) + return 0; + + size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size); + new_groupinfo = kvzalloc(size, GFP_KERNEL); + if (!new_groupinfo) { + ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group"); + return -ENOMEM; + } + rcu_read_lock(); + old_groupinfo = rcu_dereference(sbi->s_group_info); + if (old_groupinfo) + memcpy(new_groupinfo, old_groupinfo, + sbi->s_group_info_size * sizeof(*sbi->s_group_info)); + rcu_read_unlock(); + rcu_assign_pointer(sbi->s_group_info, new_groupinfo); + sbi->s_group_info_size = size / sizeof(*sbi->s_group_info); + if (old_groupinfo) + ext4_kvfree_array_rcu(old_groupinfo); + ext4_debug("allocated s_groupinfo array for %d meta_bg's\n", + sbi->s_group_info_size); + return 0; +} + +/* Create and initialize ext4_group_info data for the given group. */ +int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group, + struct ext4_group_desc *desc) +{ + int i; + int metalen = 0; + int idx = group >> EXT4_DESC_PER_BLOCK_BITS(sb); + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_group_info **meta_group_info; + struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits); + + /* + * First check if this group is the first of a reserved block. + * If it's true, we have to allocate a new table of pointers + * to ext4_group_info structures + */ + if (group % EXT4_DESC_PER_BLOCK(sb) == 0) { + metalen = sizeof(*meta_group_info) << + EXT4_DESC_PER_BLOCK_BITS(sb); + meta_group_info = kmalloc(metalen, GFP_NOFS); + if (meta_group_info == NULL) { + ext4_msg(sb, KERN_ERR, "can't allocate mem " + "for a buddy group"); + return -ENOMEM; + } + rcu_read_lock(); + rcu_dereference(sbi->s_group_info)[idx] = meta_group_info; + rcu_read_unlock(); + } + + meta_group_info = sbi_array_rcu_deref(sbi, s_group_info, idx); + i = group & (EXT4_DESC_PER_BLOCK(sb) - 1); + + meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS); + if (meta_group_info[i] == NULL) { + ext4_msg(sb, KERN_ERR, "can't allocate buddy mem"); + goto exit_group_info; + } + set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, + &(meta_group_info[i]->bb_state)); + + /* + * initialize bb_free to be able to skip + * empty groups without initialization + */ + if (ext4_has_group_desc_csum(sb) && + (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { + meta_group_info[i]->bb_free = + ext4_free_clusters_after_init(sb, group, desc); + } else { + meta_group_info[i]->bb_free = + ext4_free_group_clusters(sb, desc); + } + + INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list); + init_rwsem(&meta_group_info[i]->alloc_sem); + meta_group_info[i]->bb_free_root = RB_ROOT; + meta_group_info[i]->bb_largest_free_order = -1; /* uninit */ + meta_group_info[i]->bb_avg_fragment_size_order = -1; /* uninit */ + meta_group_info[i]->bb_group = group; + + mb_group_bb_bitmap_alloc(sb, meta_group_info[i], group); + return 0; + +exit_group_info: + /* If a meta_group_info table has been allocated, release it now */ + if (group % EXT4_DESC_PER_BLOCK(sb) == 0) { + struct ext4_group_info ***group_info; + + rcu_read_lock(); + group_info = rcu_dereference(sbi->s_group_info); + kfree(group_info[idx]); + group_info[idx] = NULL; + rcu_read_unlock(); + } + return -ENOMEM; +} /* ext4_mb_add_groupinfo */ + +static int ext4_mb_init_backend(struct super_block *sb) +{ + ext4_group_t ngroups = ext4_get_groups_count(sb); + ext4_group_t i; + struct ext4_sb_info *sbi = EXT4_SB(sb); + int err; + struct ext4_group_desc *desc; + struct ext4_group_info ***group_info; + struct kmem_cache *cachep; + + err = ext4_mb_alloc_groupinfo(sb, ngroups); + if (err) + return err; + + sbi->s_buddy_cache = new_inode(sb); + if (sbi->s_buddy_cache == NULL) { + ext4_msg(sb, KERN_ERR, "can't get new inode"); + goto err_freesgi; + } + /* To avoid potentially colliding with an valid on-disk inode number, + * use EXT4_BAD_INO for the buddy cache inode number. This inode is + * not in the inode hash, so it should never be found by iget(), but + * this will avoid confusion if it ever shows up during debugging. */ + sbi->s_buddy_cache->i_ino = EXT4_BAD_INO; + EXT4_I(sbi->s_buddy_cache)->i_disksize = 0; + for (i = 0; i < ngroups; i++) { + cond_resched(); + desc = ext4_get_group_desc(sb, i, NULL); + if (desc == NULL) { + ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i); + goto err_freebuddy; + } + if (ext4_mb_add_groupinfo(sb, i, desc) != 0) + goto err_freebuddy; + } + + if (ext4_has_feature_flex_bg(sb)) { + /* a single flex group is supposed to be read by a single IO. + * 2 ^ s_log_groups_per_flex != UINT_MAX as s_mb_prefetch is + * unsigned integer, so the maximum shift is 32. + */ + if (sbi->s_es->s_log_groups_per_flex >= 32) { + ext4_msg(sb, KERN_ERR, "too many log groups per flexible block group"); + goto err_freebuddy; + } + sbi->s_mb_prefetch = min_t(uint, 1 << sbi->s_es->s_log_groups_per_flex, + BLK_MAX_SEGMENT_SIZE >> (sb->s_blocksize_bits - 9)); + sbi->s_mb_prefetch *= 8; /* 8 prefetch IOs in flight at most */ + } else { + sbi->s_mb_prefetch = 32; + } + if (sbi->s_mb_prefetch > ext4_get_groups_count(sb)) + sbi->s_mb_prefetch = ext4_get_groups_count(sb); + /* + * now many real IOs to prefetch within a single allocation at + * CR_POWER2_ALIGNED. Given CR_POWER2_ALIGNED is an CPU-related + * optimization we shouldn't try to load too many groups, at some point + * we should start to use what we've got in memory. + * with an average random access time 5ms, it'd take a second to get + * 200 groups (* N with flex_bg), so let's make this limit 4 + */ + sbi->s_mb_prefetch_limit = sbi->s_mb_prefetch * 4; + if (sbi->s_mb_prefetch_limit > ext4_get_groups_count(sb)) + sbi->s_mb_prefetch_limit = ext4_get_groups_count(sb); + + return 0; + +err_freebuddy: + cachep = get_groupinfo_cache(sb->s_blocksize_bits); + while (i-- > 0) { + struct ext4_group_info *grp = ext4_get_group_info(sb, i); + + if (grp) + kmem_cache_free(cachep, grp); + } + i = sbi->s_group_info_size; + rcu_read_lock(); + group_info = rcu_dereference(sbi->s_group_info); + while (i-- > 0) + kfree(group_info[i]); + rcu_read_unlock(); + iput(sbi->s_buddy_cache); +err_freesgi: + rcu_read_lock(); + kvfree(rcu_dereference(sbi->s_group_info)); + rcu_read_unlock(); + return -ENOMEM; +} + +static void ext4_groupinfo_destroy_slabs(void) +{ + int i; + + for (i = 0; i < NR_GRPINFO_CACHES; i++) { + kmem_cache_destroy(ext4_groupinfo_caches[i]); + ext4_groupinfo_caches[i] = NULL; + } +} + +static int ext4_groupinfo_create_slab(size_t size) +{ + static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex); + int slab_size; + int blocksize_bits = order_base_2(size); + int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE; + struct kmem_cache *cachep; + + if (cache_index >= NR_GRPINFO_CACHES) + return -EINVAL; + + if (unlikely(cache_index < 0)) + cache_index = 0; + + mutex_lock(&ext4_grpinfo_slab_create_mutex); + if (ext4_groupinfo_caches[cache_index]) { + mutex_unlock(&ext4_grpinfo_slab_create_mutex); + return 0; /* Already created */ + } + + slab_size = offsetof(struct ext4_group_info, + bb_counters[blocksize_bits + 2]); + + cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index], + slab_size, 0, SLAB_RECLAIM_ACCOUNT, + NULL); + + ext4_groupinfo_caches[cache_index] = cachep; + + mutex_unlock(&ext4_grpinfo_slab_create_mutex); + if (!cachep) { + printk(KERN_EMERG + "EXT4-fs: no memory for groupinfo slab cache\n"); + return -ENOMEM; + } + + return 0; +} + +static void ext4_discard_work(struct work_struct *work) +{ + struct ext4_sb_info *sbi = container_of(work, + struct ext4_sb_info, s_discard_work); + struct super_block *sb = sbi->s_sb; + struct ext4_free_data *fd, *nfd; + struct ext4_buddy e4b; + LIST_HEAD(discard_list); + ext4_group_t grp, load_grp; + int err = 0; + + spin_lock(&sbi->s_md_lock); + list_splice_init(&sbi->s_discard_list, &discard_list); + spin_unlock(&sbi->s_md_lock); + + load_grp = UINT_MAX; + list_for_each_entry_safe(fd, nfd, &discard_list, efd_list) { + /* + * If filesystem is umounting or no memory or suffering + * from no space, give up the discard + */ + if ((sb->s_flags & SB_ACTIVE) && !err && + !atomic_read(&sbi->s_retry_alloc_pending)) { + grp = fd->efd_group; + if (grp != load_grp) { + if (load_grp != UINT_MAX) + ext4_mb_unload_buddy(&e4b); + + err = ext4_mb_load_buddy(sb, grp, &e4b); + if (err) { + kmem_cache_free(ext4_free_data_cachep, fd); + load_grp = UINT_MAX; + continue; + } else { + load_grp = grp; + } + } + + ext4_lock_group(sb, grp); + ext4_try_to_trim_range(sb, &e4b, fd->efd_start_cluster, + fd->efd_start_cluster + fd->efd_count - 1, 1); + ext4_unlock_group(sb, grp); + } + kmem_cache_free(ext4_free_data_cachep, fd); + } + + if (load_grp != UINT_MAX) + ext4_mb_unload_buddy(&e4b); +} + +static inline void ext4_mb_avg_fragment_size_destroy(struct ext4_sb_info *sbi) +{ + if (!sbi->s_mb_avg_fragment_size) + return; + + for (int i = 0; i < MB_NUM_ORDERS(sbi->s_sb); i++) + xa_destroy(&sbi->s_mb_avg_fragment_size[i]); + + kfree(sbi->s_mb_avg_fragment_size); + sbi->s_mb_avg_fragment_size = NULL; +} + +static inline void ext4_mb_largest_free_orders_destroy(struct ext4_sb_info *sbi) +{ + if (!sbi->s_mb_largest_free_orders) + return; + + for (int i = 0; i < MB_NUM_ORDERS(sbi->s_sb); i++) + xa_destroy(&sbi->s_mb_largest_free_orders[i]); + + kfree(sbi->s_mb_largest_free_orders); + sbi->s_mb_largest_free_orders = NULL; +} + +int ext4_mb_init(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + unsigned i, j; + unsigned offset, offset_incr; + unsigned max; + int ret; + + i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_offsets); + + sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL); + if (sbi->s_mb_offsets == NULL) { + ret = -ENOMEM; + goto out; + } + + i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_maxs); + sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL); + if (sbi->s_mb_maxs == NULL) { + ret = -ENOMEM; + goto out; + } + + ret = ext4_groupinfo_create_slab(sb->s_blocksize); + if (ret < 0) + goto out; + + /* order 0 is regular bitmap */ + sbi->s_mb_maxs[0] = sb->s_blocksize << 3; + sbi->s_mb_offsets[0] = 0; + + i = 1; + offset = 0; + offset_incr = 1 << (sb->s_blocksize_bits - 1); + max = sb->s_blocksize << 2; + do { + sbi->s_mb_offsets[i] = offset; + sbi->s_mb_maxs[i] = max; + offset += offset_incr; + offset_incr = offset_incr >> 1; + max = max >> 1; + i++; + } while (i < MB_NUM_ORDERS(sb)); + + sbi->s_mb_avg_fragment_size = + kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct xarray), + GFP_KERNEL); + if (!sbi->s_mb_avg_fragment_size) { + ret = -ENOMEM; + goto out; + } + for (i = 0; i < MB_NUM_ORDERS(sb); i++) + xa_init(&sbi->s_mb_avg_fragment_size[i]); + + sbi->s_mb_largest_free_orders = + kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct xarray), + GFP_KERNEL); + if (!sbi->s_mb_largest_free_orders) { + ret = -ENOMEM; + goto out; + } + for (i = 0; i < MB_NUM_ORDERS(sb); i++) + xa_init(&sbi->s_mb_largest_free_orders[i]); + + spin_lock_init(&sbi->s_md_lock); + atomic_set(&sbi->s_mb_free_pending, 0); + INIT_LIST_HEAD(&sbi->s_freed_data_list[0]); + INIT_LIST_HEAD(&sbi->s_freed_data_list[1]); + INIT_LIST_HEAD(&sbi->s_discard_list); + INIT_WORK(&sbi->s_discard_work, ext4_discard_work); + atomic_set(&sbi->s_retry_alloc_pending, 0); + + sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN; + sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN; + sbi->s_mb_stats = MB_DEFAULT_STATS; + sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD; + sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS; + sbi->s_mb_best_avail_max_trim_order = MB_DEFAULT_BEST_AVAIL_TRIM_ORDER; + + /* + * The default group preallocation is 512, which for 4k block + * sizes translates to 2 megabytes. However for bigalloc file + * systems, this is probably too big (i.e, if the cluster size + * is 1 megabyte, then group preallocation size becomes half a + * gigabyte!). As a default, we will keep a two megabyte + * group pralloc size for cluster sizes up to 64k, and after + * that, we will force a minimum group preallocation size of + * 32 clusters. This translates to 8 megs when the cluster + * size is 256k, and 32 megs when the cluster size is 1 meg, + * which seems reasonable as a default. + */ + sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >> + sbi->s_cluster_bits, 32); + /* + * If there is a s_stripe > 1, then we set the s_mb_group_prealloc + * to the lowest multiple of s_stripe which is bigger than + * the s_mb_group_prealloc as determined above. We want + * the preallocation size to be an exact multiple of the + * RAID stripe size so that preallocations don't fragment + * the stripes. + */ + if (sbi->s_stripe > 1) { + sbi->s_mb_group_prealloc = roundup( + sbi->s_mb_group_prealloc, EXT4_NUM_B2C(sbi, sbi->s_stripe)); + } + + sbi->s_mb_nr_global_goals = umin(num_possible_cpus(), + DIV_ROUND_UP(sbi->s_groups_count, 4)); + sbi->s_mb_last_groups = kcalloc(sbi->s_mb_nr_global_goals, + sizeof(ext4_group_t), GFP_KERNEL); + if (sbi->s_mb_last_groups == NULL) { + ret = -ENOMEM; + goto out; + } + + sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group); + if (sbi->s_locality_groups == NULL) { + ret = -ENOMEM; + goto out_free_last_groups; + } + for_each_possible_cpu(i) { + struct ext4_locality_group *lg; + lg = per_cpu_ptr(sbi->s_locality_groups, i); + mutex_init(&lg->lg_mutex); + for (j = 0; j < PREALLOC_TB_SIZE; j++) + INIT_LIST_HEAD(&lg->lg_prealloc_list[j]); + spin_lock_init(&lg->lg_prealloc_lock); + } + + if (bdev_nonrot(sb->s_bdev)) + sbi->s_mb_max_linear_groups = 0; + else + sbi->s_mb_max_linear_groups = MB_DEFAULT_LINEAR_LIMIT; + /* init file for buddy data */ + ret = ext4_mb_init_backend(sb); + if (ret != 0) + goto out_free_locality_groups; + + return 0; + +out_free_locality_groups: + free_percpu(sbi->s_locality_groups); + sbi->s_locality_groups = NULL; +out_free_last_groups: + kfree(sbi->s_mb_last_groups); + sbi->s_mb_last_groups = NULL; +out: + ext4_mb_avg_fragment_size_destroy(sbi); + ext4_mb_largest_free_orders_destroy(sbi); + kfree(sbi->s_mb_offsets); + sbi->s_mb_offsets = NULL; + kfree(sbi->s_mb_maxs); + sbi->s_mb_maxs = NULL; + return ret; +} + +/* need to called with the ext4 group lock held */ +static int ext4_mb_cleanup_pa(struct ext4_group_info *grp) +{ + struct ext4_prealloc_space *pa; + struct list_head *cur, *tmp; + int count = 0; + + list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) { + pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list); + list_del(&pa->pa_group_list); + count++; + kmem_cache_free(ext4_pspace_cachep, pa); + } + return count; +} + +void ext4_mb_release(struct super_block *sb) +{ + ext4_group_t ngroups = ext4_get_groups_count(sb); + ext4_group_t i; + int num_meta_group_infos; + struct ext4_group_info *grinfo, ***group_info; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits); + int count; + + if (test_opt(sb, DISCARD)) { + /* + * wait the discard work to drain all of ext4_free_data + */ + flush_work(&sbi->s_discard_work); + WARN_ON_ONCE(!list_empty(&sbi->s_discard_list)); + } + + if (sbi->s_group_info) { + for (i = 0; i < ngroups; i++) { + cond_resched(); + grinfo = ext4_get_group_info(sb, i); + if (!grinfo) + continue; + mb_group_bb_bitmap_free(grinfo); + ext4_lock_group(sb, i); + count = ext4_mb_cleanup_pa(grinfo); + if (count) + mb_debug(sb, "mballoc: %d PAs left\n", + count); + ext4_unlock_group(sb, i); + kmem_cache_free(cachep, grinfo); + } + num_meta_group_infos = (ngroups + + EXT4_DESC_PER_BLOCK(sb) - 1) >> + EXT4_DESC_PER_BLOCK_BITS(sb); + rcu_read_lock(); + group_info = rcu_dereference(sbi->s_group_info); + for (i = 0; i < num_meta_group_infos; i++) + kfree(group_info[i]); + kvfree(group_info); + rcu_read_unlock(); + } + ext4_mb_avg_fragment_size_destroy(sbi); + ext4_mb_largest_free_orders_destroy(sbi); + kfree(sbi->s_mb_offsets); + kfree(sbi->s_mb_maxs); + iput(sbi->s_buddy_cache); + if (sbi->s_mb_stats) { + ext4_msg(sb, KERN_INFO, + "mballoc: %u blocks %u reqs (%u success)", + atomic_read(&sbi->s_bal_allocated), + atomic_read(&sbi->s_bal_reqs), + atomic_read(&sbi->s_bal_success)); + ext4_msg(sb, KERN_INFO, + "mballoc: %u extents scanned, %u groups scanned, %u goal hits, " + "%u 2^N hits, %u breaks, %u lost", + atomic_read(&sbi->s_bal_ex_scanned), + atomic_read(&sbi->s_bal_groups_scanned), + atomic_read(&sbi->s_bal_goals), + atomic_read(&sbi->s_bal_2orders), + atomic_read(&sbi->s_bal_breaks), + atomic_read(&sbi->s_mb_lost_chunks)); + ext4_msg(sb, KERN_INFO, + "mballoc: %u generated and it took %llu", + atomic_read(&sbi->s_mb_buddies_generated), + atomic64_read(&sbi->s_mb_generation_time)); + ext4_msg(sb, KERN_INFO, + "mballoc: %u preallocated, %u discarded", + atomic_read(&sbi->s_mb_preallocated), + atomic_read(&sbi->s_mb_discarded)); + } + + free_percpu(sbi->s_locality_groups); + kfree(sbi->s_mb_last_groups); +} + +static inline int ext4_issue_discard(struct super_block *sb, + ext4_group_t block_group, ext4_grpblk_t cluster, int count) +{ + ext4_fsblk_t discard_block; + + discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) + + ext4_group_first_block_no(sb, block_group)); + count = EXT4_C2B(EXT4_SB(sb), count); + trace_ext4_discard_blocks(sb, + (unsigned long long) discard_block, count); + + return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0); +} + +static void ext4_free_data_in_buddy(struct super_block *sb, + struct ext4_free_data *entry) +{ + struct ext4_buddy e4b; + struct ext4_group_info *db; + int err, count = 0; + + mb_debug(sb, "gonna free %u blocks in group %u (0x%p):", + entry->efd_count, entry->efd_group, entry); + + err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b); + /* we expect to find existing buddy because it's pinned */ + BUG_ON(err != 0); + + atomic_sub(entry->efd_count, &EXT4_SB(sb)->s_mb_free_pending); + db = e4b.bd_info; + /* there are blocks to put in buddy to make them really free */ + count += entry->efd_count; + ext4_lock_group(sb, entry->efd_group); + /* Take it out of per group rb tree */ + rb_erase(&entry->efd_node, &(db->bb_free_root)); + mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count); + + /* + * Clear the trimmed flag for the group so that the next + * ext4_trim_fs can trim it. + */ + EXT4_MB_GRP_CLEAR_TRIMMED(db); + + if (!db->bb_free_root.rb_node) { + /* No more items in the per group rb tree + * balance refcounts from ext4_mb_free_metadata() + */ + folio_put(e4b.bd_buddy_folio); + folio_put(e4b.bd_bitmap_folio); + } + ext4_unlock_group(sb, entry->efd_group); + ext4_mb_unload_buddy(&e4b); + + mb_debug(sb, "freed %d blocks in 1 structures\n", count); +} + +/* + * This function is called by the jbd2 layer once the commit has finished, + * so we know we can free the blocks that were released with that commit. + */ +void ext4_process_freed_data(struct super_block *sb, tid_t commit_tid) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_free_data *entry, *tmp; + LIST_HEAD(freed_data_list); + struct list_head *s_freed_head = &sbi->s_freed_data_list[commit_tid & 1]; + bool wake; + + list_replace_init(s_freed_head, &freed_data_list); + + list_for_each_entry(entry, &freed_data_list, efd_list) + ext4_free_data_in_buddy(sb, entry); + + if (test_opt(sb, DISCARD)) { + spin_lock(&sbi->s_md_lock); + wake = list_empty(&sbi->s_discard_list); + list_splice_tail(&freed_data_list, &sbi->s_discard_list); + spin_unlock(&sbi->s_md_lock); + if (wake) + queue_work(system_dfl_wq, &sbi->s_discard_work); + } else { + list_for_each_entry_safe(entry, tmp, &freed_data_list, efd_list) + kmem_cache_free(ext4_free_data_cachep, entry); + } +} + +int __init ext4_init_mballoc(void) +{ + ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space, + SLAB_RECLAIM_ACCOUNT); + if (ext4_pspace_cachep == NULL) + goto out; + + ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context, + SLAB_RECLAIM_ACCOUNT); + if (ext4_ac_cachep == NULL) + goto out_pa_free; + + ext4_free_data_cachep = KMEM_CACHE(ext4_free_data, + SLAB_RECLAIM_ACCOUNT); + if (ext4_free_data_cachep == NULL) + goto out_ac_free; + + return 0; + +out_ac_free: + kmem_cache_destroy(ext4_ac_cachep); +out_pa_free: + kmem_cache_destroy(ext4_pspace_cachep); +out: + return -ENOMEM; +} + +void ext4_exit_mballoc(void) +{ + /* + * Wait for completion of call_rcu()'s on ext4_pspace_cachep + * before destroying the slab cache. + */ + rcu_barrier(); + kmem_cache_destroy(ext4_pspace_cachep); + kmem_cache_destroy(ext4_ac_cachep); + kmem_cache_destroy(ext4_free_data_cachep); + ext4_groupinfo_destroy_slabs(); +} + +#define EXT4_MB_BITMAP_MARKED_CHECK 0x0001 +#define EXT4_MB_SYNC_UPDATE 0x0002 +static int +ext4_mb_mark_context(handle_t *handle, struct super_block *sb, bool state, + ext4_group_t group, ext4_grpblk_t blkoff, + ext4_grpblk_t len, int flags, ext4_grpblk_t *ret_changed) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct buffer_head *bitmap_bh = NULL; + struct ext4_group_desc *gdp; + struct buffer_head *gdp_bh; + int err; + unsigned int i, already, changed = len; + + KUNIT_STATIC_STUB_REDIRECT(ext4_mb_mark_context, + handle, sb, state, group, blkoff, len, + flags, ret_changed); + + if (ret_changed) + *ret_changed = 0; + bitmap_bh = ext4_read_block_bitmap(sb, group); + if (IS_ERR(bitmap_bh)) + return PTR_ERR(bitmap_bh); + + if (handle) { + BUFFER_TRACE(bitmap_bh, "getting write access"); + err = ext4_journal_get_write_access(handle, sb, bitmap_bh, + EXT4_JTR_NONE); + if (err) + goto out_err; + } + + err = -EIO; + gdp = ext4_get_group_desc(sb, group, &gdp_bh); + if (!gdp) + goto out_err; + + if (handle) { + BUFFER_TRACE(gdp_bh, "get_write_access"); + err = ext4_journal_get_write_access(handle, sb, gdp_bh, + EXT4_JTR_NONE); + if (err) + goto out_err; + } + + ext4_lock_group(sb, group); + if (ext4_has_group_desc_csum(sb) && + (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { + gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT); + ext4_free_group_clusters_set(sb, gdp, + ext4_free_clusters_after_init(sb, group, gdp)); + } + + if (flags & EXT4_MB_BITMAP_MARKED_CHECK) { + already = 0; + for (i = 0; i < len; i++) + if (mb_test_bit(blkoff + i, bitmap_bh->b_data) == + state) + already++; + changed = len - already; + } + + if (state) { + mb_set_bits(bitmap_bh->b_data, blkoff, len); + ext4_free_group_clusters_set(sb, gdp, + ext4_free_group_clusters(sb, gdp) - changed); + } else { + mb_clear_bits(bitmap_bh->b_data, blkoff, len); + ext4_free_group_clusters_set(sb, gdp, + ext4_free_group_clusters(sb, gdp) + changed); + } + + ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh); + ext4_group_desc_csum_set(sb, group, gdp); + ext4_unlock_group(sb, group); + if (ret_changed) + *ret_changed = changed; + + if (sbi->s_log_groups_per_flex) { + ext4_group_t flex_group = ext4_flex_group(sbi, group); + struct flex_groups *fg = sbi_array_rcu_deref(sbi, + s_flex_groups, flex_group); + + if (state) + atomic64_sub(changed, &fg->free_clusters); + else + atomic64_add(changed, &fg->free_clusters); + } + + err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh); + if (err) + goto out_err; + err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh); + if (err) + goto out_err; + + if (flags & EXT4_MB_SYNC_UPDATE) { + sync_dirty_buffer(bitmap_bh); + sync_dirty_buffer(gdp_bh); + } + +out_err: + brelse(bitmap_bh); + return err; +} + +/* + * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps + * Returns 0 if success or error code + */ +static noinline_for_stack int +ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, + handle_t *handle, unsigned int reserv_clstrs) +{ + struct ext4_group_desc *gdp; + struct ext4_sb_info *sbi; + struct super_block *sb; + ext4_fsblk_t block; + int err, len; + int flags = 0; + ext4_grpblk_t changed; + + BUG_ON(ac->ac_status != AC_STATUS_FOUND); + BUG_ON(ac->ac_b_ex.fe_len <= 0); + + sb = ac->ac_sb; + sbi = EXT4_SB(sb); + + gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, NULL); + if (!gdp) + return -EIO; + ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group, + ext4_free_group_clusters(sb, gdp)); + + block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); + len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len); + if (!ext4_inode_block_valid(ac->ac_inode, block, len)) { + ext4_error(sb, "Allocating blocks %llu-%llu which overlap " + "fs metadata", block, block+len); + /* File system mounted not to panic on error + * Fix the bitmap and return EFSCORRUPTED + * We leak some of the blocks here. + */ + err = ext4_mb_mark_context(handle, sb, true, + ac->ac_b_ex.fe_group, + ac->ac_b_ex.fe_start, + ac->ac_b_ex.fe_len, + 0, NULL); + if (!err) + err = -EFSCORRUPTED; + return err; + } + +#ifdef AGGRESSIVE_CHECK + flags |= EXT4_MB_BITMAP_MARKED_CHECK; +#endif + err = ext4_mb_mark_context(handle, sb, true, ac->ac_b_ex.fe_group, + ac->ac_b_ex.fe_start, ac->ac_b_ex.fe_len, + flags, &changed); + + if (err && changed == 0) + return err; + +#ifdef AGGRESSIVE_CHECK + BUG_ON(changed != ac->ac_b_ex.fe_len); +#endif + percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len); + /* + * Now reduce the dirty block count also. Should not go negative + */ + if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED)) + /* release all the reserved blocks if non delalloc */ + percpu_counter_sub(&sbi->s_dirtyclusters_counter, + reserv_clstrs); + + return err; +} + +/* + * Idempotent helper for Ext4 fast commit replay path to set the state of + * blocks in bitmaps and update counters. + */ +void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block, + int len, bool state) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_group_t group; + ext4_grpblk_t blkoff; + int err = 0; + unsigned int clen, thisgrp_len; + + while (len > 0) { + ext4_get_group_no_and_offset(sb, block, &group, &blkoff); + + /* + * Check to see if we are freeing blocks across a group + * boundary. + * In case of flex_bg, this can happen that (block, len) may + * span across more than one group. In that case we need to + * get the corresponding group metadata to work with. + * For this we have goto again loop. + */ + thisgrp_len = min_t(unsigned int, (unsigned int)len, + EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff)); + clen = EXT4_NUM_B2C(sbi, thisgrp_len); + + if (!ext4_sb_block_valid(sb, NULL, block, thisgrp_len)) { + ext4_error(sb, "Marking blocks in system zone - " + "Block = %llu, len = %u", + block, thisgrp_len); + break; + } + + err = ext4_mb_mark_context(NULL, sb, state, + group, blkoff, clen, + EXT4_MB_BITMAP_MARKED_CHECK | + EXT4_MB_SYNC_UPDATE, + NULL); + if (err) + break; + + block += thisgrp_len; + len -= thisgrp_len; + BUG_ON(len < 0); + } +} + +/* + * here we normalize request for locality group + * Group request are normalized to s_mb_group_prealloc, which goes to + * s_strip if we set the same via mount option. + * s_mb_group_prealloc can be configured via + * /sys/fs/ext4/<partition>/mb_group_prealloc + * + * XXX: should we try to preallocate more than the group has now? + */ +static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_locality_group *lg = ac->ac_lg; + + BUG_ON(lg == NULL); + ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc; + mb_debug(sb, "goal %u blocks for locality group\n", ac->ac_g_ex.fe_len); +} + +/* + * This function returns the next element to look at during inode + * PA rbtree walk. We assume that we have held the inode PA rbtree lock + * (ei->i_prealloc_lock) + * + * new_start The start of the range we want to compare + * cur_start The existing start that we are comparing against + * node The node of the rb_tree + */ +static inline struct rb_node* +ext4_mb_pa_rb_next_iter(ext4_lblk_t new_start, ext4_lblk_t cur_start, struct rb_node *node) +{ + if (new_start < cur_start) + return node->rb_left; + else + return node->rb_right; +} + +static inline void +ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac, + ext4_lblk_t start, loff_t end) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); + struct ext4_prealloc_space *tmp_pa; + ext4_lblk_t tmp_pa_start; + loff_t tmp_pa_end; + struct rb_node *iter; + + read_lock(&ei->i_prealloc_lock); + for (iter = ei->i_prealloc_node.rb_node; iter; + iter = ext4_mb_pa_rb_next_iter(start, tmp_pa_start, iter)) { + tmp_pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); + tmp_pa_start = tmp_pa->pa_lstart; + tmp_pa_end = pa_logical_end(sbi, tmp_pa); + + spin_lock(&tmp_pa->pa_lock); + if (tmp_pa->pa_deleted == 0) + BUG_ON(!(start >= tmp_pa_end || end <= tmp_pa_start)); + spin_unlock(&tmp_pa->pa_lock); + } + read_unlock(&ei->i_prealloc_lock); +} + +/* + * Given an allocation context "ac" and a range "start", "end", check + * and adjust boundaries if the range overlaps with any of the existing + * preallocatoins stored in the corresponding inode of the allocation context. + * + * Parameters: + * ac allocation context + * start start of the new range + * end end of the new range + */ +static inline void +ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac, + ext4_lblk_t *start, loff_t *end) +{ + struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + struct ext4_prealloc_space *tmp_pa = NULL, *left_pa = NULL, *right_pa = NULL; + struct rb_node *iter; + ext4_lblk_t new_start, tmp_pa_start, right_pa_start = -1; + loff_t new_end, tmp_pa_end, left_pa_end = -1; + + new_start = *start; + new_end = *end; + + /* + * Adjust the normalized range so that it doesn't overlap with any + * existing preallocated blocks(PAs). Make sure to hold the rbtree lock + * so it doesn't change underneath us. + */ + read_lock(&ei->i_prealloc_lock); + + /* Step 1: find any one immediate neighboring PA of the normalized range */ + for (iter = ei->i_prealloc_node.rb_node; iter; + iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical, + tmp_pa_start, iter)) { + tmp_pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); + tmp_pa_start = tmp_pa->pa_lstart; + tmp_pa_end = pa_logical_end(sbi, tmp_pa); + + /* PA must not overlap original request */ + spin_lock(&tmp_pa->pa_lock); + if (tmp_pa->pa_deleted == 0) + BUG_ON(!(ac->ac_o_ex.fe_logical >= tmp_pa_end || + ac->ac_o_ex.fe_logical < tmp_pa_start)); + spin_unlock(&tmp_pa->pa_lock); + } + + /* + * Step 2: check if the found PA is left or right neighbor and + * get the other neighbor + */ + if (tmp_pa) { + if (tmp_pa->pa_lstart < ac->ac_o_ex.fe_logical) { + struct rb_node *tmp; + + left_pa = tmp_pa; + tmp = rb_next(&left_pa->pa_node.inode_node); + if (tmp) { + right_pa = rb_entry(tmp, + struct ext4_prealloc_space, + pa_node.inode_node); + } + } else { + struct rb_node *tmp; + + right_pa = tmp_pa; + tmp = rb_prev(&right_pa->pa_node.inode_node); + if (tmp) { + left_pa = rb_entry(tmp, + struct ext4_prealloc_space, + pa_node.inode_node); + } + } + } + + /* Step 3: get the non deleted neighbors */ + if (left_pa) { + for (iter = &left_pa->pa_node.inode_node;; + iter = rb_prev(iter)) { + if (!iter) { + left_pa = NULL; + break; + } + + tmp_pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); + left_pa = tmp_pa; + spin_lock(&tmp_pa->pa_lock); + if (tmp_pa->pa_deleted == 0) { + spin_unlock(&tmp_pa->pa_lock); + break; + } + spin_unlock(&tmp_pa->pa_lock); + } + } + + if (right_pa) { + for (iter = &right_pa->pa_node.inode_node;; + iter = rb_next(iter)) { + if (!iter) { + right_pa = NULL; + break; + } + + tmp_pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); + right_pa = tmp_pa; + spin_lock(&tmp_pa->pa_lock); + if (tmp_pa->pa_deleted == 0) { + spin_unlock(&tmp_pa->pa_lock); + break; + } + spin_unlock(&tmp_pa->pa_lock); + } + } + + if (left_pa) { + left_pa_end = pa_logical_end(sbi, left_pa); + BUG_ON(left_pa_end > ac->ac_o_ex.fe_logical); + } + + if (right_pa) { + right_pa_start = right_pa->pa_lstart; + BUG_ON(right_pa_start <= ac->ac_o_ex.fe_logical); + } + + /* Step 4: trim our normalized range to not overlap with the neighbors */ + if (left_pa) { + if (left_pa_end > new_start) + new_start = left_pa_end; + } + + if (right_pa) { + if (right_pa_start < new_end) + new_end = right_pa_start; + } + read_unlock(&ei->i_prealloc_lock); + + /* XXX: extra loop to check we really don't overlap preallocations */ + ext4_mb_pa_assert_overlap(ac, new_start, new_end); + + *start = new_start; + *end = new_end; +} + +/* + * Normalization means making request better in terms of + * size and alignment + */ +static noinline_for_stack void +ext4_mb_normalize_request(struct ext4_allocation_context *ac, + struct ext4_allocation_request *ar) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + struct ext4_super_block *es = sbi->s_es; + int bsbits, max; + loff_t size, start_off, end; + loff_t orig_size __maybe_unused; + ext4_lblk_t start; + + /* do normalize only data requests, metadata requests + do not need preallocation */ + if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) + return; + + /* sometime caller may want exact blocks */ + if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) + return; + + /* caller may indicate that preallocation isn't + * required (it's a tail, for example) */ + if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC) + return; + + if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) { + ext4_mb_normalize_group_request(ac); + return ; + } + + bsbits = ac->ac_sb->s_blocksize_bits; + + /* first, let's learn actual file size + * given current request is allocated */ + size = extent_logical_end(sbi, &ac->ac_o_ex); + size = size << bsbits; + if (size < i_size_read(ac->ac_inode)) + size = i_size_read(ac->ac_inode); + orig_size = size; + + /* max size of free chunks */ + max = 2 << bsbits; + +#define NRL_CHECK_SIZE(req, size, max, chunk_size) \ + (req <= (size) || max <= (chunk_size)) + + /* first, try to predict filesize */ + /* XXX: should this table be tunable? */ + start_off = 0; + if (size <= 16 * 1024) { + size = 16 * 1024; + } else if (size <= 32 * 1024) { + size = 32 * 1024; + } else if (size <= 64 * 1024) { + size = 64 * 1024; + } else if (size <= 128 * 1024) { + size = 128 * 1024; + } else if (size <= 256 * 1024) { + size = 256 * 1024; + } else if (size <= 512 * 1024) { + size = 512 * 1024; + } else if (size <= 1024 * 1024) { + size = 1024 * 1024; + } else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) { + start_off = ((loff_t)ac->ac_o_ex.fe_logical >> + (21 - bsbits)) << 21; + size = 2 * 1024 * 1024; + } else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) { + start_off = ((loff_t)ac->ac_o_ex.fe_logical >> + (22 - bsbits)) << 22; + size = 4 * 1024 * 1024; + } else if (NRL_CHECK_SIZE(EXT4_C2B(sbi, ac->ac_o_ex.fe_len), + (8<<20)>>bsbits, max, 8 * 1024)) { + start_off = ((loff_t)ac->ac_o_ex.fe_logical >> + (23 - bsbits)) << 23; + size = 8 * 1024 * 1024; + } else { + start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits; + size = (loff_t) EXT4_C2B(sbi, + ac->ac_o_ex.fe_len) << bsbits; + } + size = size >> bsbits; + start = start_off >> bsbits; + + /* + * For tiny groups (smaller than 8MB) the chosen allocation + * alignment may be larger than group size. Make sure the + * alignment does not move allocation to a different group which + * makes mballoc fail assertions later. + */ + start = max(start, rounddown(ac->ac_o_ex.fe_logical, + (ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb))); + + /* avoid unnecessary preallocation that may trigger assertions */ + if (start + size > EXT_MAX_BLOCKS) + size = EXT_MAX_BLOCKS - start; + + /* don't cover already allocated blocks in selected range */ + if (ar->pleft && start <= ar->lleft) { + size -= ar->lleft + 1 - start; + start = ar->lleft + 1; + } + if (ar->pright && start + size - 1 >= ar->lright) + size -= start + size - ar->lright; + + /* + * Trim allocation request for filesystems with artificially small + * groups. + */ + if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb)) + size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb); + + end = start + size; + + ext4_mb_pa_adjust_overlap(ac, &start, &end); + + size = end - start; + + /* + * In this function "start" and "size" are normalized for better + * alignment and length such that we could preallocate more blocks. + * This normalization is done such that original request of + * ac->ac_o_ex.fe_logical & fe_len should always lie within "start" and + * "size" boundaries. + * (Note fe_len can be relaxed since FS block allocation API does not + * provide gurantee on number of contiguous blocks allocation since that + * depends upon free space left, etc). + * In case of inode pa, later we use the allocated blocks + * [pa_pstart + fe_logical - pa_lstart, fe_len/size] from the preallocated + * range of goal/best blocks [start, size] to put it at the + * ac_o_ex.fe_logical extent of this inode. + * (See ext4_mb_use_inode_pa() for more details) + */ + if (start + size <= ac->ac_o_ex.fe_logical || + start > ac->ac_o_ex.fe_logical) { + ext4_msg(ac->ac_sb, KERN_ERR, + "start %lu, size %lu, fe_logical %lu", + (unsigned long) start, (unsigned long) size, + (unsigned long) ac->ac_o_ex.fe_logical); + BUG(); + } + BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb)); + + /* now prepare goal request */ + + /* XXX: is it better to align blocks WRT to logical + * placement or satisfy big request as is */ + ac->ac_g_ex.fe_logical = start; + ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size); + ac->ac_orig_goal_len = ac->ac_g_ex.fe_len; + + /* define goal start in order to merge */ + if (ar->pright && (ar->lright == (start + size)) && + ar->pright >= size && + ar->pright - size >= le32_to_cpu(es->s_first_data_block)) { + /* merge to the right */ + ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size, + &ac->ac_g_ex.fe_group, + &ac->ac_g_ex.fe_start); + ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL; + } + if (ar->pleft && (ar->lleft + 1 == start) && + ar->pleft + 1 < ext4_blocks_count(es)) { + /* merge to the left */ + ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1, + &ac->ac_g_ex.fe_group, + &ac->ac_g_ex.fe_start); + ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL; + } + + mb_debug(ac->ac_sb, "goal: %lld(was %lld) blocks at %u\n", size, + orig_size, start); +} + +static void ext4_mb_collect_stats(struct ext4_allocation_context *ac) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + + if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) { + atomic_inc(&sbi->s_bal_reqs); + atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated); + if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len) + atomic_inc(&sbi->s_bal_success); + + atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned); + for (int i=0; i<EXT4_MB_NUM_CRS; i++) { + atomic_add(ac->ac_cX_found[i], &sbi->s_bal_cX_ex_scanned[i]); + } + + atomic_add(ac->ac_groups_scanned, &sbi->s_bal_groups_scanned); + if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start && + ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group) + atomic_inc(&sbi->s_bal_goals); + /* did we allocate as much as normalizer originally wanted? */ + if (ac->ac_f_ex.fe_len == ac->ac_orig_goal_len) + atomic_inc(&sbi->s_bal_len_goals); + + if (ac->ac_found > sbi->s_mb_max_to_scan) + atomic_inc(&sbi->s_bal_breaks); + } + + if (ac->ac_op == EXT4_MB_HISTORY_ALLOC) + trace_ext4_mballoc_alloc(ac); + else + trace_ext4_mballoc_prealloc(ac); +} + +/* + * Called on failure; free up any blocks from the inode PA for this + * context. We don't need this for MB_GROUP_PA because we only change + * pa_free in ext4_mb_release_context(), but on failure, we've already + * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed. + */ +static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac) +{ + struct ext4_prealloc_space *pa = ac->ac_pa; + struct ext4_buddy e4b; + int err; + + if (pa == NULL) { + if (ac->ac_f_ex.fe_len == 0) + return; + err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b); + if (WARN_RATELIMIT(err, + "ext4: mb_load_buddy failed (%d)", err)) + /* + * This should never happen since we pin the + * pages in the ext4_allocation_context so + * ext4_mb_load_buddy() should never fail. + */ + return; + ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group); + mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start, + ac->ac_f_ex.fe_len); + ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group); + ext4_mb_unload_buddy(&e4b); + return; + } + if (pa->pa_type == MB_INODE_PA) { + spin_lock(&pa->pa_lock); + pa->pa_free += ac->ac_b_ex.fe_len; + spin_unlock(&pa->pa_lock); + } +} + +/* + * use blocks preallocated to inode + */ +static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac, + struct ext4_prealloc_space *pa) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + ext4_fsblk_t start; + ext4_fsblk_t end; + int len; + + /* found preallocated blocks, use them */ + start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart); + end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len), + start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len)); + len = EXT4_NUM_B2C(sbi, end - start); + ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group, + &ac->ac_b_ex.fe_start); + ac->ac_b_ex.fe_len = len; + ac->ac_status = AC_STATUS_FOUND; + ac->ac_pa = pa; + + BUG_ON(start < pa->pa_pstart); + BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len)); + BUG_ON(pa->pa_free < len); + BUG_ON(ac->ac_b_ex.fe_len <= 0); + pa->pa_free -= len; + + mb_debug(ac->ac_sb, "use %llu/%d from inode pa %p\n", start, len, pa); +} + +/* + * use blocks preallocated to locality group + */ +static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac, + struct ext4_prealloc_space *pa) +{ + unsigned int len = ac->ac_o_ex.fe_len; + + ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart, + &ac->ac_b_ex.fe_group, + &ac->ac_b_ex.fe_start); + ac->ac_b_ex.fe_len = len; + ac->ac_status = AC_STATUS_FOUND; + ac->ac_pa = pa; + + /* we don't correct pa_pstart or pa_len here to avoid + * possible race when the group is being loaded concurrently + * instead we correct pa later, after blocks are marked + * in on-disk bitmap -- see ext4_mb_release_context() + * Other CPUs are prevented from allocating from this pa by lg_mutex + */ + mb_debug(ac->ac_sb, "use %u/%u from group pa %p\n", + pa->pa_lstart, len, pa); +} + +/* + * Return the prealloc space that have minimal distance + * from the goal block. @cpa is the prealloc + * space that is having currently known minimal distance + * from the goal block. + */ +static struct ext4_prealloc_space * +ext4_mb_check_group_pa(ext4_fsblk_t goal_block, + struct ext4_prealloc_space *pa, + struct ext4_prealloc_space *cpa) +{ + ext4_fsblk_t cur_distance, new_distance; + + if (cpa == NULL) { + atomic_inc(&pa->pa_count); + return pa; + } + cur_distance = abs(goal_block - cpa->pa_pstart); + new_distance = abs(goal_block - pa->pa_pstart); + + if (cur_distance <= new_distance) + return cpa; + + /* drop the previous reference */ + atomic_dec(&cpa->pa_count); + atomic_inc(&pa->pa_count); + return pa; +} + +/* + * check if found pa meets EXT4_MB_HINT_GOAL_ONLY + */ +static bool +ext4_mb_pa_goal_check(struct ext4_allocation_context *ac, + struct ext4_prealloc_space *pa) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + ext4_fsblk_t start; + + if (likely(!(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))) + return true; + + /* + * If EXT4_MB_HINT_GOAL_ONLY is set, ac_g_ex will not be adjusted + * in ext4_mb_normalize_request and will keep same with ac_o_ex + * from ext4_mb_initialize_context. Choose ac_g_ex here to keep + * consistent with ext4_mb_find_by_goal. + */ + start = pa->pa_pstart + + (ac->ac_g_ex.fe_logical - pa->pa_lstart); + if (ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex) != start) + return false; + + if (ac->ac_g_ex.fe_len > pa->pa_len - + EXT4_B2C(sbi, ac->ac_g_ex.fe_logical - pa->pa_lstart)) + return false; + + return true; +} + +/* + * search goal blocks in preallocated space + */ +static noinline_for_stack bool +ext4_mb_use_preallocated(struct ext4_allocation_context *ac) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + int order, i; + struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); + struct ext4_locality_group *lg; + struct ext4_prealloc_space *tmp_pa = NULL, *cpa = NULL; + struct rb_node *iter; + ext4_fsblk_t goal_block; + + /* only data can be preallocated */ + if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) + return false; + + /* + * first, try per-file preallocation by searching the inode pa rbtree. + * + * Here, we can't do a direct traversal of the tree because + * ext4_mb_discard_group_preallocation() can paralelly mark the pa + * deleted and that can cause direct traversal to skip some entries. + */ + read_lock(&ei->i_prealloc_lock); + + if (RB_EMPTY_ROOT(&ei->i_prealloc_node)) { + goto try_group_pa; + } + + /* + * Step 1: Find a pa with logical start immediately adjacent to the + * original logical start. This could be on the left or right. + * + * (tmp_pa->pa_lstart never changes so we can skip locking for it). + */ + for (iter = ei->i_prealloc_node.rb_node; iter; + iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical, + tmp_pa->pa_lstart, iter)) { + tmp_pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); + } + + /* + * Step 2: The adjacent pa might be to the right of logical start, find + * the left adjacent pa. After this step we'd have a valid tmp_pa whose + * logical start is towards the left of original request's logical start + */ + if (tmp_pa->pa_lstart > ac->ac_o_ex.fe_logical) { + struct rb_node *tmp; + tmp = rb_prev(&tmp_pa->pa_node.inode_node); + + if (tmp) { + tmp_pa = rb_entry(tmp, struct ext4_prealloc_space, + pa_node.inode_node); + } else { + /* + * If there is no adjacent pa to the left then finding + * an overlapping pa is not possible hence stop searching + * inode pa tree + */ + goto try_group_pa; + } + } + + BUG_ON(!(tmp_pa && tmp_pa->pa_lstart <= ac->ac_o_ex.fe_logical)); + + /* + * Step 3: If the left adjacent pa is deleted, keep moving left to find + * the first non deleted adjacent pa. After this step we should have a + * valid tmp_pa which is guaranteed to be non deleted. + */ + for (iter = &tmp_pa->pa_node.inode_node;; iter = rb_prev(iter)) { + if (!iter) { + /* + * no non deleted left adjacent pa, so stop searching + * inode pa tree + */ + goto try_group_pa; + } + tmp_pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); + spin_lock(&tmp_pa->pa_lock); + if (tmp_pa->pa_deleted == 0) { + /* + * We will keep holding the pa_lock from + * this point on because we don't want group discard + * to delete this pa underneath us. Since group + * discard is anyways an ENOSPC operation it + * should be okay for it to wait a few more cycles. + */ + break; + } else { + spin_unlock(&tmp_pa->pa_lock); + } + } + + BUG_ON(!(tmp_pa && tmp_pa->pa_lstart <= ac->ac_o_ex.fe_logical)); + BUG_ON(tmp_pa->pa_deleted == 1); + + /* + * Step 4: We now have the non deleted left adjacent pa. Only this + * pa can possibly satisfy the request hence check if it overlaps + * original logical start and stop searching if it doesn't. + */ + if (ac->ac_o_ex.fe_logical >= pa_logical_end(sbi, tmp_pa)) { + spin_unlock(&tmp_pa->pa_lock); + goto try_group_pa; + } + + /* non-extent files can't have physical blocks past 2^32 */ + if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) && + (tmp_pa->pa_pstart + EXT4_C2B(sbi, tmp_pa->pa_len) > + EXT4_MAX_BLOCK_FILE_PHYS)) { + /* + * Since PAs don't overlap, we won't find any other PA to + * satisfy this. + */ + spin_unlock(&tmp_pa->pa_lock); + goto try_group_pa; + } + + if (tmp_pa->pa_free && likely(ext4_mb_pa_goal_check(ac, tmp_pa))) { + atomic_inc(&tmp_pa->pa_count); + ext4_mb_use_inode_pa(ac, tmp_pa); + spin_unlock(&tmp_pa->pa_lock); + read_unlock(&ei->i_prealloc_lock); + return true; + } else { + /* + * We found a valid overlapping pa but couldn't use it because + * it had no free blocks. This should ideally never happen + * because: + * + * 1. When a new inode pa is added to rbtree it must have + * pa_free > 0 since otherwise we won't actually need + * preallocation. + * + * 2. An inode pa that is in the rbtree can only have it's + * pa_free become zero when another thread calls: + * ext4_mb_new_blocks + * ext4_mb_use_preallocated + * ext4_mb_use_inode_pa + * + * 3. Further, after the above calls make pa_free == 0, we will + * immediately remove it from the rbtree in: + * ext4_mb_new_blocks + * ext4_mb_release_context + * ext4_mb_put_pa + * + * 4. Since the pa_free becoming 0 and pa_free getting removed + * from tree both happen in ext4_mb_new_blocks, which is always + * called with i_data_sem held for data allocations, we can be + * sure that another process will never see a pa in rbtree with + * pa_free == 0. + */ + WARN_ON_ONCE(tmp_pa->pa_free == 0); + } + spin_unlock(&tmp_pa->pa_lock); +try_group_pa: + read_unlock(&ei->i_prealloc_lock); + + /* can we use group allocation? */ + if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)) + return false; + + /* inode may have no locality group for some reason */ + lg = ac->ac_lg; + if (lg == NULL) + return false; + order = fls(ac->ac_o_ex.fe_len) - 1; + if (order > PREALLOC_TB_SIZE - 1) + /* The max size of hash table is PREALLOC_TB_SIZE */ + order = PREALLOC_TB_SIZE - 1; + + goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex); + /* + * search for the prealloc space that is having + * minimal distance from the goal block. + */ + for (i = order; i < PREALLOC_TB_SIZE; i++) { + rcu_read_lock(); + list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[i], + pa_node.lg_list) { + spin_lock(&tmp_pa->pa_lock); + if (tmp_pa->pa_deleted == 0 && + tmp_pa->pa_free >= ac->ac_o_ex.fe_len) { + + cpa = ext4_mb_check_group_pa(goal_block, + tmp_pa, cpa); + } + spin_unlock(&tmp_pa->pa_lock); + } + rcu_read_unlock(); + } + if (cpa) { + ext4_mb_use_group_pa(ac, cpa); + return true; + } + return false; +} + +/* + * the function goes through all preallocation in this group and marks them + * used in in-core bitmap. buddy must be generated from this bitmap + * Need to be called with ext4 group lock held + */ +static noinline_for_stack +void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, + ext4_group_t group) +{ + struct ext4_group_info *grp = ext4_get_group_info(sb, group); + struct ext4_prealloc_space *pa; + struct list_head *cur; + ext4_group_t groupnr; + ext4_grpblk_t start; + int preallocated = 0; + int len; + + if (!grp) + return; + + /* all form of preallocation discards first load group, + * so the only competing code is preallocation use. + * we don't need any locking here + * notice we do NOT ignore preallocations with pa_deleted + * otherwise we could leave used blocks available for + * allocation in buddy when concurrent ext4_mb_put_pa() + * is dropping preallocation + */ + list_for_each(cur, &grp->bb_prealloc_list) { + pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list); + spin_lock(&pa->pa_lock); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, + &groupnr, &start); + len = pa->pa_len; + spin_unlock(&pa->pa_lock); + if (unlikely(len == 0)) + continue; + BUG_ON(groupnr != group); + mb_set_bits(bitmap, start, len); + preallocated += len; + } + mb_debug(sb, "preallocated %d for group %u\n", preallocated, group); +} + +static void ext4_mb_mark_pa_deleted(struct super_block *sb, + struct ext4_prealloc_space *pa) +{ + struct ext4_inode_info *ei; + + if (pa->pa_deleted) { + ext4_warning(sb, "deleted pa, type:%d, pblk:%llu, lblk:%u, len:%d\n", + pa->pa_type, pa->pa_pstart, pa->pa_lstart, + pa->pa_len); + return; + } + + pa->pa_deleted = 1; + + if (pa->pa_type == MB_INODE_PA) { + ei = EXT4_I(pa->pa_inode); + atomic_dec(&ei->i_prealloc_active); + } +} + +static inline void ext4_mb_pa_free(struct ext4_prealloc_space *pa) +{ + BUG_ON(!pa); + BUG_ON(atomic_read(&pa->pa_count)); + BUG_ON(pa->pa_deleted == 0); + kmem_cache_free(ext4_pspace_cachep, pa); +} + +static void ext4_mb_pa_callback(struct rcu_head *head) +{ + struct ext4_prealloc_space *pa; + + pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu); + ext4_mb_pa_free(pa); +} + +/* + * drops a reference to preallocated space descriptor + * if this was the last reference and the space is consumed + */ +static void ext4_mb_put_pa(struct ext4_allocation_context *ac, + struct super_block *sb, struct ext4_prealloc_space *pa) +{ + ext4_group_t grp; + ext4_fsblk_t grp_blk; + struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); + + /* in this short window concurrent discard can set pa_deleted */ + spin_lock(&pa->pa_lock); + if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) { + spin_unlock(&pa->pa_lock); + return; + } + + if (pa->pa_deleted == 1) { + spin_unlock(&pa->pa_lock); + return; + } + + ext4_mb_mark_pa_deleted(sb, pa); + spin_unlock(&pa->pa_lock); + + grp_blk = pa->pa_pstart; + /* + * If doing group-based preallocation, pa_pstart may be in the + * next group when pa is used up + */ + if (pa->pa_type == MB_GROUP_PA) + grp_blk--; + + grp = ext4_get_group_number(sb, grp_blk); + + /* + * possible race: + * + * P1 (buddy init) P2 (regular allocation) + * find block B in PA + * copy on-disk bitmap to buddy + * mark B in on-disk bitmap + * drop PA from group + * mark all PAs in buddy + * + * thus, P1 initializes buddy with B available. to prevent this + * we make "copy" and "mark all PAs" atomic and serialize "drop PA" + * against that pair + */ + ext4_lock_group(sb, grp); + list_del(&pa->pa_group_list); + ext4_unlock_group(sb, grp); + + if (pa->pa_type == MB_INODE_PA) { + write_lock(pa->pa_node_lock.inode_lock); + rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node); + write_unlock(pa->pa_node_lock.inode_lock); + ext4_mb_pa_free(pa); + } else { + spin_lock(pa->pa_node_lock.lg_lock); + list_del_rcu(&pa->pa_node.lg_list); + spin_unlock(pa->pa_node_lock.lg_lock); + call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); + } +} + +static void ext4_mb_pa_rb_insert(struct rb_root *root, struct rb_node *new) +{ + struct rb_node **iter = &root->rb_node, *parent = NULL; + struct ext4_prealloc_space *iter_pa, *new_pa; + ext4_lblk_t iter_start, new_start; + + while (*iter) { + iter_pa = rb_entry(*iter, struct ext4_prealloc_space, + pa_node.inode_node); + new_pa = rb_entry(new, struct ext4_prealloc_space, + pa_node.inode_node); + iter_start = iter_pa->pa_lstart; + new_start = new_pa->pa_lstart; + + parent = *iter; + if (new_start < iter_start) + iter = &((*iter)->rb_left); + else + iter = &((*iter)->rb_right); + } + + rb_link_node(new, parent, iter); + rb_insert_color(new, root); +} + +/* + * creates new preallocated space for given inode + */ +static noinline_for_stack void +ext4_mb_new_inode_pa(struct ext4_allocation_context *ac) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_prealloc_space *pa; + struct ext4_group_info *grp; + struct ext4_inode_info *ei; + + /* preallocate only when found space is larger then requested */ + BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len); + BUG_ON(ac->ac_status != AC_STATUS_FOUND); + BUG_ON(!S_ISREG(ac->ac_inode->i_mode)); + BUG_ON(ac->ac_pa == NULL); + + pa = ac->ac_pa; + + if (ac->ac_b_ex.fe_len < ac->ac_orig_goal_len) { + struct ext4_free_extent ex = { + .fe_logical = ac->ac_g_ex.fe_logical, + .fe_len = ac->ac_orig_goal_len, + }; + loff_t orig_goal_end = extent_logical_end(sbi, &ex); + loff_t o_ex_end = extent_logical_end(sbi, &ac->ac_o_ex); + + /* + * We can't allocate as much as normalizer wants, so we try + * to get proper lstart to cover the original request, except + * when the goal doesn't cover the original request as below: + * + * orig_ex:2045/2055(10), isize:8417280 -> normalized:0/2048 + * best_ex:0/200(200) -> adjusted: 1848/2048(200) + */ + BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical); + BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len); + + /* + * Use the below logic for adjusting best extent as it keeps + * fragmentation in check while ensuring logical range of best + * extent doesn't overflow out of goal extent: + * + * 1. Check if best ex can be kept at end of goal (before + * cr_best_avail trimmed it) and still cover original start + * 2. Else, check if best ex can be kept at start of goal and + * still cover original end + * 3. Else, keep the best ex at start of original request. + */ + ex.fe_len = ac->ac_b_ex.fe_len; + + ex.fe_logical = orig_goal_end - EXT4_C2B(sbi, ex.fe_len); + if (ac->ac_o_ex.fe_logical >= ex.fe_logical) + goto adjust_bex; + + ex.fe_logical = ac->ac_g_ex.fe_logical; + if (o_ex_end <= extent_logical_end(sbi, &ex)) + goto adjust_bex; + + ex.fe_logical = ac->ac_o_ex.fe_logical; +adjust_bex: + ac->ac_b_ex.fe_logical = ex.fe_logical; + + BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical); + BUG_ON(extent_logical_end(sbi, &ex) > orig_goal_end); + } + + pa->pa_lstart = ac->ac_b_ex.fe_logical; + pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); + pa->pa_len = ac->ac_b_ex.fe_len; + pa->pa_free = pa->pa_len; + spin_lock_init(&pa->pa_lock); + INIT_LIST_HEAD(&pa->pa_group_list); + pa->pa_deleted = 0; + pa->pa_type = MB_INODE_PA; + + mb_debug(sb, "new inode pa %p: %llu/%d for %u\n", pa, pa->pa_pstart, + pa->pa_len, pa->pa_lstart); + trace_ext4_mb_new_inode_pa(ac, pa); + + atomic_add(pa->pa_free, &sbi->s_mb_preallocated); + ext4_mb_use_inode_pa(ac, pa); + + ei = EXT4_I(ac->ac_inode); + grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group); + if (!grp) + return; + + pa->pa_node_lock.inode_lock = &ei->i_prealloc_lock; + pa->pa_inode = ac->ac_inode; + + list_add(&pa->pa_group_list, &grp->bb_prealloc_list); + + write_lock(pa->pa_node_lock.inode_lock); + ext4_mb_pa_rb_insert(&ei->i_prealloc_node, &pa->pa_node.inode_node); + write_unlock(pa->pa_node_lock.inode_lock); + atomic_inc(&ei->i_prealloc_active); +} + +/* + * creates new preallocated space for locality group inodes belongs to + */ +static noinline_for_stack void +ext4_mb_new_group_pa(struct ext4_allocation_context *ac) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_locality_group *lg; + struct ext4_prealloc_space *pa; + struct ext4_group_info *grp; + + /* preallocate only when found space is larger then requested */ + BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len); + BUG_ON(ac->ac_status != AC_STATUS_FOUND); + BUG_ON(!S_ISREG(ac->ac_inode->i_mode)); + BUG_ON(ac->ac_pa == NULL); + + pa = ac->ac_pa; + + pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); + pa->pa_lstart = pa->pa_pstart; + pa->pa_len = ac->ac_b_ex.fe_len; + pa->pa_free = pa->pa_len; + spin_lock_init(&pa->pa_lock); + INIT_LIST_HEAD(&pa->pa_node.lg_list); + INIT_LIST_HEAD(&pa->pa_group_list); + pa->pa_deleted = 0; + pa->pa_type = MB_GROUP_PA; + + mb_debug(sb, "new group pa %p: %llu/%d for %u\n", pa, pa->pa_pstart, + pa->pa_len, pa->pa_lstart); + trace_ext4_mb_new_group_pa(ac, pa); + + ext4_mb_use_group_pa(ac, pa); + atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated); + + grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group); + if (!grp) + return; + lg = ac->ac_lg; + BUG_ON(lg == NULL); + + pa->pa_node_lock.lg_lock = &lg->lg_prealloc_lock; + pa->pa_inode = NULL; + + list_add(&pa->pa_group_list, &grp->bb_prealloc_list); + + /* + * We will later add the new pa to the right bucket + * after updating the pa_free in ext4_mb_release_context + */ +} + +static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac) +{ + if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) + ext4_mb_new_group_pa(ac); + else + ext4_mb_new_inode_pa(ac); +} + +/* + * finds all unused blocks in on-disk bitmap, frees them in + * in-core bitmap and buddy. + * @pa must be unlinked from inode and group lists, so that + * nobody else can find/use it. + * the caller MUST hold group/inode locks. + * TODO: optimize the case when there are no in-core structures yet + */ +static noinline_for_stack void +ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh, + struct ext4_prealloc_space *pa) +{ + struct super_block *sb = e4b->bd_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + unsigned int end; + unsigned int next; + ext4_group_t group; + ext4_grpblk_t bit; + unsigned long long grp_blk_start; + int free = 0; + + BUG_ON(pa->pa_deleted == 0); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit); + grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit); + BUG_ON(group != e4b->bd_group && pa->pa_len != 0); + end = bit + pa->pa_len; + + while (bit < end) { + bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit); + if (bit >= end) + break; + next = mb_find_next_bit(bitmap_bh->b_data, end, bit); + mb_debug(sb, "free preallocated %u/%u in group %u\n", + (unsigned) ext4_group_first_block_no(sb, group) + bit, + (unsigned) next - bit, (unsigned) group); + free += next - bit; + + trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit); + trace_ext4_mb_release_inode_pa(pa, (grp_blk_start + + EXT4_C2B(sbi, bit)), + next - bit); + mb_free_blocks(pa->pa_inode, e4b, bit, next - bit); + bit = next + 1; + } + if (free != pa->pa_free) { + ext4_msg(e4b->bd_sb, KERN_CRIT, + "pa %p: logic %lu, phys. %lu, len %d", + pa, (unsigned long) pa->pa_lstart, + (unsigned long) pa->pa_pstart, + pa->pa_len); + ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u", + free, pa->pa_free); + /* + * pa is already deleted so we use the value obtained + * from the bitmap and continue. + */ + } + atomic_add(free, &sbi->s_mb_discarded); +} + +static noinline_for_stack void +ext4_mb_release_group_pa(struct ext4_buddy *e4b, + struct ext4_prealloc_space *pa) +{ + struct super_block *sb = e4b->bd_sb; + ext4_group_t group; + ext4_grpblk_t bit; + + trace_ext4_mb_release_group_pa(sb, pa); + BUG_ON(pa->pa_deleted == 0); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit); + if (unlikely(group != e4b->bd_group && pa->pa_len != 0)) { + ext4_warning(sb, "bad group: expected %u, group %u, pa_start %llu", + e4b->bd_group, group, pa->pa_pstart); + return; + } + mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len); + atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded); + trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len); +} + +/* + * releases all preallocations in given group + * + * first, we need to decide discard policy: + * - when do we discard + * 1) ENOSPC + * - how many do we discard + * 1) how many requested + */ +static noinline_for_stack int +ext4_mb_discard_group_preallocations(struct super_block *sb, + ext4_group_t group, int *busy) +{ + struct ext4_group_info *grp = ext4_get_group_info(sb, group); + struct buffer_head *bitmap_bh = NULL; + struct ext4_prealloc_space *pa, *tmp; + LIST_HEAD(list); + struct ext4_buddy e4b; + struct ext4_inode_info *ei; + int err; + int free = 0; + + if (!grp) + return 0; + mb_debug(sb, "discard preallocation for group %u\n", group); + if (list_empty(&grp->bb_prealloc_list)) + goto out_dbg; + + bitmap_bh = ext4_read_block_bitmap(sb, group); + if (IS_ERR(bitmap_bh)) { + err = PTR_ERR(bitmap_bh); + ext4_error_err(sb, -err, + "Error %d reading block bitmap for %u", + err, group); + goto out_dbg; + } + + err = ext4_mb_load_buddy(sb, group, &e4b); + if (err) { + ext4_warning(sb, "Error %d loading buddy information for %u", + err, group); + put_bh(bitmap_bh); + goto out_dbg; + } + + ext4_lock_group(sb, group); + list_for_each_entry_safe(pa, tmp, + &grp->bb_prealloc_list, pa_group_list) { + spin_lock(&pa->pa_lock); + if (atomic_read(&pa->pa_count)) { + spin_unlock(&pa->pa_lock); + *busy = 1; + continue; + } + if (pa->pa_deleted) { + spin_unlock(&pa->pa_lock); + continue; + } + + /* seems this one can be freed ... */ + ext4_mb_mark_pa_deleted(sb, pa); + + if (!free) + this_cpu_inc(discard_pa_seq); + + /* we can trust pa_free ... */ + free += pa->pa_free; + + spin_unlock(&pa->pa_lock); + + list_del(&pa->pa_group_list); + list_add(&pa->u.pa_tmp_list, &list); + } + + /* now free all selected PAs */ + list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) { + + /* remove from object (inode or locality group) */ + if (pa->pa_type == MB_GROUP_PA) { + spin_lock(pa->pa_node_lock.lg_lock); + list_del_rcu(&pa->pa_node.lg_list); + spin_unlock(pa->pa_node_lock.lg_lock); + } else { + write_lock(pa->pa_node_lock.inode_lock); + ei = EXT4_I(pa->pa_inode); + rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node); + write_unlock(pa->pa_node_lock.inode_lock); + } + + list_del(&pa->u.pa_tmp_list); + + if (pa->pa_type == MB_GROUP_PA) { + ext4_mb_release_group_pa(&e4b, pa); + call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); + } else { + ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa); + ext4_mb_pa_free(pa); + } + } + + ext4_unlock_group(sb, group); + ext4_mb_unload_buddy(&e4b); + put_bh(bitmap_bh); +out_dbg: + mb_debug(sb, "discarded (%d) blocks preallocated for group %u bb_free (%d)\n", + free, group, grp->bb_free); + return free; +} + +/* + * releases all non-used preallocated blocks for given inode + * + * It's important to discard preallocations under i_data_sem + * We don't want another block to be served from the prealloc + * space when we are discarding the inode prealloc space. + * + * FIXME!! Make sure it is valid at all the call sites + */ +void ext4_discard_preallocations(struct inode *inode) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + struct super_block *sb = inode->i_sb; + struct buffer_head *bitmap_bh = NULL; + struct ext4_prealloc_space *pa, *tmp; + ext4_group_t group = 0; + LIST_HEAD(list); + struct ext4_buddy e4b; + struct rb_node *iter; + int err; + + if (!S_ISREG(inode->i_mode)) + return; + + if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) + return; + + mb_debug(sb, "discard preallocation for inode %lu\n", + inode->i_ino); + trace_ext4_discard_preallocations(inode, + atomic_read(&ei->i_prealloc_active)); + +repeat: + /* first, collect all pa's in the inode */ + write_lock(&ei->i_prealloc_lock); + for (iter = rb_first(&ei->i_prealloc_node); iter; + iter = rb_next(iter)) { + pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); + BUG_ON(pa->pa_node_lock.inode_lock != &ei->i_prealloc_lock); + + spin_lock(&pa->pa_lock); + if (atomic_read(&pa->pa_count)) { + /* this shouldn't happen often - nobody should + * use preallocation while we're discarding it */ + spin_unlock(&pa->pa_lock); + write_unlock(&ei->i_prealloc_lock); + ext4_msg(sb, KERN_ERR, + "uh-oh! used pa while discarding"); + WARN_ON(1); + schedule_timeout_uninterruptible(HZ); + goto repeat; + + } + if (pa->pa_deleted == 0) { + ext4_mb_mark_pa_deleted(sb, pa); + spin_unlock(&pa->pa_lock); + rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node); + list_add(&pa->u.pa_tmp_list, &list); + continue; + } + + /* someone is deleting pa right now */ + spin_unlock(&pa->pa_lock); + write_unlock(&ei->i_prealloc_lock); + + /* we have to wait here because pa_deleted + * doesn't mean pa is already unlinked from + * the list. as we might be called from + * ->clear_inode() the inode will get freed + * and concurrent thread which is unlinking + * pa from inode's list may access already + * freed memory, bad-bad-bad */ + + /* XXX: if this happens too often, we can + * add a flag to force wait only in case + * of ->clear_inode(), but not in case of + * regular truncate */ + schedule_timeout_uninterruptible(HZ); + goto repeat; + } + write_unlock(&ei->i_prealloc_lock); + + list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) { + BUG_ON(pa->pa_type != MB_INODE_PA); + group = ext4_get_group_number(sb, pa->pa_pstart); + + err = ext4_mb_load_buddy_gfp(sb, group, &e4b, + GFP_NOFS|__GFP_NOFAIL); + if (err) { + ext4_error_err(sb, -err, "Error %d loading buddy information for %u", + err, group); + continue; + } + + bitmap_bh = ext4_read_block_bitmap(sb, group); + if (IS_ERR(bitmap_bh)) { + err = PTR_ERR(bitmap_bh); + ext4_error_err(sb, -err, "Error %d reading block bitmap for %u", + err, group); + ext4_mb_unload_buddy(&e4b); + continue; + } + + ext4_lock_group(sb, group); + list_del(&pa->pa_group_list); + ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa); + ext4_unlock_group(sb, group); + + ext4_mb_unload_buddy(&e4b); + put_bh(bitmap_bh); + + list_del(&pa->u.pa_tmp_list); + ext4_mb_pa_free(pa); + } +} + +static int ext4_mb_pa_alloc(struct ext4_allocation_context *ac) +{ + struct ext4_prealloc_space *pa; + + BUG_ON(ext4_pspace_cachep == NULL); + pa = kmem_cache_zalloc(ext4_pspace_cachep, GFP_NOFS); + if (!pa) + return -ENOMEM; + atomic_set(&pa->pa_count, 1); + ac->ac_pa = pa; + return 0; +} + +static void ext4_mb_pa_put_free(struct ext4_allocation_context *ac) +{ + struct ext4_prealloc_space *pa = ac->ac_pa; + + BUG_ON(!pa); + ac->ac_pa = NULL; + WARN_ON(!atomic_dec_and_test(&pa->pa_count)); + /* + * current function is only called due to an error or due to + * len of found blocks < len of requested blocks hence the PA has not + * been added to grp->bb_prealloc_list. So we don't need to lock it + */ + pa->pa_deleted = 1; + ext4_mb_pa_free(pa); +} + +#ifdef CONFIG_EXT4_DEBUG +static inline void ext4_mb_show_pa(struct super_block *sb) +{ + ext4_group_t i, ngroups; + + if (ext4_emergency_state(sb)) + return; + + ngroups = ext4_get_groups_count(sb); + mb_debug(sb, "groups: "); + for (i = 0; i < ngroups; i++) { + struct ext4_group_info *grp = ext4_get_group_info(sb, i); + struct ext4_prealloc_space *pa; + ext4_grpblk_t start; + struct list_head *cur; + + if (!grp) + continue; + ext4_lock_group(sb, i); + list_for_each(cur, &grp->bb_prealloc_list) { + pa = list_entry(cur, struct ext4_prealloc_space, + pa_group_list); + spin_lock(&pa->pa_lock); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, + NULL, &start); + spin_unlock(&pa->pa_lock); + mb_debug(sb, "PA:%u:%d:%d\n", i, start, + pa->pa_len); + } + ext4_unlock_group(sb, i); + mb_debug(sb, "%u: %d/%d\n", i, grp->bb_free, + grp->bb_fragments); + } +} + +static void ext4_mb_show_ac(struct ext4_allocation_context *ac) +{ + struct super_block *sb = ac->ac_sb; + + if (ext4_emergency_state(sb)) + return; + + mb_debug(sb, "Can't allocate:" + " Allocation context details:"); + mb_debug(sb, "status %u flags 0x%x", + ac->ac_status, ac->ac_flags); + mb_debug(sb, "orig %lu/%lu/%lu@%lu, " + "goal %lu/%lu/%lu@%lu, " + "best %lu/%lu/%lu@%lu cr %d", + (unsigned long)ac->ac_o_ex.fe_group, + (unsigned long)ac->ac_o_ex.fe_start, + (unsigned long)ac->ac_o_ex.fe_len, + (unsigned long)ac->ac_o_ex.fe_logical, + (unsigned long)ac->ac_g_ex.fe_group, + (unsigned long)ac->ac_g_ex.fe_start, + (unsigned long)ac->ac_g_ex.fe_len, + (unsigned long)ac->ac_g_ex.fe_logical, + (unsigned long)ac->ac_b_ex.fe_group, + (unsigned long)ac->ac_b_ex.fe_start, + (unsigned long)ac->ac_b_ex.fe_len, + (unsigned long)ac->ac_b_ex.fe_logical, + (int)ac->ac_criteria); + mb_debug(sb, "%u found", ac->ac_found); + mb_debug(sb, "used pa: %s, ", str_yes_no(ac->ac_pa)); + if (ac->ac_pa) + mb_debug(sb, "pa_type %s\n", ac->ac_pa->pa_type == MB_GROUP_PA ? + "group pa" : "inode pa"); + ext4_mb_show_pa(sb); +} +#else +static inline void ext4_mb_show_pa(struct super_block *sb) +{ +} +static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac) +{ + ext4_mb_show_pa(ac->ac_sb); +} +#endif + +/* + * We use locality group preallocation for small size file. The size of the + * file is determined by the current size or the resulting size after + * allocation which ever is larger + * + * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req + */ +static void ext4_mb_group_or_file(struct ext4_allocation_context *ac) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + int bsbits = ac->ac_sb->s_blocksize_bits; + loff_t size, isize; + bool inode_pa_eligible, group_pa_eligible; + + if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) + return; + + if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) + return; + + group_pa_eligible = sbi->s_mb_group_prealloc > 0; + inode_pa_eligible = true; + size = extent_logical_end(sbi, &ac->ac_o_ex); + isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1) + >> bsbits; + + /* No point in using inode preallocation for closed files */ + if ((size == isize) && !ext4_fs_is_busy(sbi) && + !inode_is_open_for_write(ac->ac_inode)) + inode_pa_eligible = false; + + size = max(size, isize); + /* Don't use group allocation for large files */ + if (size > sbi->s_mb_stream_request) + group_pa_eligible = false; + + if (!group_pa_eligible) { + if (inode_pa_eligible) + ac->ac_flags |= EXT4_MB_STREAM_ALLOC; + else + ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC; + return; + } + + BUG_ON(ac->ac_lg != NULL); + /* + * locality group prealloc space are per cpu. The reason for having + * per cpu locality group is to reduce the contention between block + * request from multiple CPUs. + */ + ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups); + + /* we're going to use group allocation */ + ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC; + + /* serialize all allocations in the group */ + mutex_lock(&ac->ac_lg->lg_mutex); +} + +static noinline_for_stack void +ext4_mb_initialize_context(struct ext4_allocation_context *ac, + struct ext4_allocation_request *ar) +{ + struct super_block *sb = ar->inode->i_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + ext4_group_t group; + unsigned int len; + ext4_fsblk_t goal; + ext4_grpblk_t block; + + /* we can't allocate > group size */ + len = ar->len; + + /* just a dirty hack to filter too big requests */ + if (len >= EXT4_CLUSTERS_PER_GROUP(sb)) + len = EXT4_CLUSTERS_PER_GROUP(sb); + + /* start searching from the goal */ + goal = ar->goal; + if (goal < le32_to_cpu(es->s_first_data_block) || + goal >= ext4_blocks_count(es)) + goal = le32_to_cpu(es->s_first_data_block); + ext4_get_group_no_and_offset(sb, goal, &group, &block); + + /* set up allocation goals */ + ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical); + ac->ac_status = AC_STATUS_CONTINUE; + ac->ac_sb = sb; + ac->ac_inode = ar->inode; + ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical; + ac->ac_o_ex.fe_group = group; + ac->ac_o_ex.fe_start = block; + ac->ac_o_ex.fe_len = len; + ac->ac_g_ex = ac->ac_o_ex; + ac->ac_orig_goal_len = ac->ac_g_ex.fe_len; + ac->ac_flags = ar->flags; + + /* we have to define context: we'll work with a file or + * locality group. this is a policy, actually */ + ext4_mb_group_or_file(ac); + + mb_debug(sb, "init ac: %u blocks @ %u, goal %u, flags 0x%x, 2^%d, " + "left: %u/%u, right %u/%u to %swritable\n", + (unsigned) ar->len, (unsigned) ar->logical, + (unsigned) ar->goal, ac->ac_flags, ac->ac_2order, + (unsigned) ar->lleft, (unsigned) ar->pleft, + (unsigned) ar->lright, (unsigned) ar->pright, + inode_is_open_for_write(ar->inode) ? "" : "non-"); +} + +static noinline_for_stack void +ext4_mb_discard_lg_preallocations(struct super_block *sb, + struct ext4_locality_group *lg, + int order, int total_entries) +{ + ext4_group_t group = 0; + struct ext4_buddy e4b; + LIST_HEAD(discard_list); + struct ext4_prealloc_space *pa, *tmp; + + mb_debug(sb, "discard locality group preallocation\n"); + + spin_lock(&lg->lg_prealloc_lock); + list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order], + pa_node.lg_list, + lockdep_is_held(&lg->lg_prealloc_lock)) { + spin_lock(&pa->pa_lock); + if (atomic_read(&pa->pa_count)) { + /* + * This is the pa that we just used + * for block allocation. So don't + * free that + */ + spin_unlock(&pa->pa_lock); + continue; + } + if (pa->pa_deleted) { + spin_unlock(&pa->pa_lock); + continue; + } + /* only lg prealloc space */ + BUG_ON(pa->pa_type != MB_GROUP_PA); + + /* seems this one can be freed ... */ + ext4_mb_mark_pa_deleted(sb, pa); + spin_unlock(&pa->pa_lock); + + list_del_rcu(&pa->pa_node.lg_list); + list_add(&pa->u.pa_tmp_list, &discard_list); + + total_entries--; + if (total_entries <= 5) { + /* + * we want to keep only 5 entries + * allowing it to grow to 8. This + * mak sure we don't call discard + * soon for this list. + */ + break; + } + } + spin_unlock(&lg->lg_prealloc_lock); + + list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) { + int err; + + group = ext4_get_group_number(sb, pa->pa_pstart); + err = ext4_mb_load_buddy_gfp(sb, group, &e4b, + GFP_NOFS|__GFP_NOFAIL); + if (err) { + ext4_error_err(sb, -err, "Error %d loading buddy information for %u", + err, group); + continue; + } + ext4_lock_group(sb, group); + list_del(&pa->pa_group_list); + ext4_mb_release_group_pa(&e4b, pa); + ext4_unlock_group(sb, group); + + ext4_mb_unload_buddy(&e4b); + list_del(&pa->u.pa_tmp_list); + call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); + } +} + +/* + * We have incremented pa_count. So it cannot be freed at this + * point. Also we hold lg_mutex. So no parallel allocation is + * possible from this lg. That means pa_free cannot be updated. + * + * A parallel ext4_mb_discard_group_preallocations is possible. + * which can cause the lg_prealloc_list to be updated. + */ + +static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac) +{ + int order, added = 0, lg_prealloc_count = 1; + struct super_block *sb = ac->ac_sb; + struct ext4_locality_group *lg = ac->ac_lg; + struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa; + + order = fls(pa->pa_free) - 1; + if (order > PREALLOC_TB_SIZE - 1) + /* The max size of hash table is PREALLOC_TB_SIZE */ + order = PREALLOC_TB_SIZE - 1; + /* Add the prealloc space to lg */ + spin_lock(&lg->lg_prealloc_lock); + list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order], + pa_node.lg_list, + lockdep_is_held(&lg->lg_prealloc_lock)) { + spin_lock(&tmp_pa->pa_lock); + if (tmp_pa->pa_deleted) { + spin_unlock(&tmp_pa->pa_lock); + continue; + } + if (!added && pa->pa_free < tmp_pa->pa_free) { + /* Add to the tail of the previous entry */ + list_add_tail_rcu(&pa->pa_node.lg_list, + &tmp_pa->pa_node.lg_list); + added = 1; + /* + * we want to count the total + * number of entries in the list + */ + } + spin_unlock(&tmp_pa->pa_lock); + lg_prealloc_count++; + } + if (!added) + list_add_tail_rcu(&pa->pa_node.lg_list, + &lg->lg_prealloc_list[order]); + spin_unlock(&lg->lg_prealloc_lock); + + /* Now trim the list to be not more than 8 elements */ + if (lg_prealloc_count > 8) + ext4_mb_discard_lg_preallocations(sb, lg, + order, lg_prealloc_count); +} + +/* + * release all resource we used in allocation + */ +static void ext4_mb_release_context(struct ext4_allocation_context *ac) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + struct ext4_prealloc_space *pa = ac->ac_pa; + if (pa) { + if (pa->pa_type == MB_GROUP_PA) { + /* see comment in ext4_mb_use_group_pa() */ + spin_lock(&pa->pa_lock); + pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len); + pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len); + pa->pa_free -= ac->ac_b_ex.fe_len; + pa->pa_len -= ac->ac_b_ex.fe_len; + spin_unlock(&pa->pa_lock); + + /* + * We want to add the pa to the right bucket. + * Remove it from the list and while adding + * make sure the list to which we are adding + * doesn't grow big. + */ + if (likely(pa->pa_free)) { + spin_lock(pa->pa_node_lock.lg_lock); + list_del_rcu(&pa->pa_node.lg_list); + spin_unlock(pa->pa_node_lock.lg_lock); + ext4_mb_add_n_trim(ac); + } + } + + ext4_mb_put_pa(ac, ac->ac_sb, pa); + } + if (ac->ac_bitmap_folio) + folio_put(ac->ac_bitmap_folio); + if (ac->ac_buddy_folio) + folio_put(ac->ac_buddy_folio); + if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) + mutex_unlock(&ac->ac_lg->lg_mutex); + ext4_mb_collect_stats(ac); +} + +static int ext4_mb_discard_preallocations(struct super_block *sb, int needed) +{ + ext4_group_t i, ngroups = ext4_get_groups_count(sb); + int ret; + int freed = 0, busy = 0; + int retry = 0; + + trace_ext4_mb_discard_preallocations(sb, needed); + + if (needed == 0) + needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1; + repeat: + for (i = 0; i < ngroups && needed > 0; i++) { + ret = ext4_mb_discard_group_preallocations(sb, i, &busy); + freed += ret; + needed -= ret; + cond_resched(); + } + + if (needed > 0 && busy && ++retry < 3) { + busy = 0; + goto repeat; + } + + return freed; +} + +static bool ext4_mb_discard_preallocations_should_retry(struct super_block *sb, + struct ext4_allocation_context *ac, u64 *seq) +{ + int freed; + u64 seq_retry = 0; + bool ret = false; + + freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len); + if (freed) { + ret = true; + goto out_dbg; + } + seq_retry = ext4_get_discard_pa_seq_sum(); + if (!(ac->ac_flags & EXT4_MB_STRICT_CHECK) || seq_retry != *seq) { + ac->ac_flags |= EXT4_MB_STRICT_CHECK; + *seq = seq_retry; + ret = true; + } + +out_dbg: + mb_debug(sb, "freed %d, retry ? %s\n", freed, str_yes_no(ret)); + return ret; +} + +/* + * Simple allocator for Ext4 fast commit replay path. It searches for blocks + * linearly starting at the goal block and also excludes the blocks which + * are going to be in use after fast commit replay. + */ +static ext4_fsblk_t +ext4_mb_new_blocks_simple(struct ext4_allocation_request *ar, int *errp) +{ + struct buffer_head *bitmap_bh; + struct super_block *sb = ar->inode->i_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_group_t group, nr; + ext4_grpblk_t blkoff; + ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb); + ext4_grpblk_t i = 0; + ext4_fsblk_t goal, block; + struct ext4_super_block *es = sbi->s_es; + + goal = ar->goal; + if (goal < le32_to_cpu(es->s_first_data_block) || + goal >= ext4_blocks_count(es)) + goal = le32_to_cpu(es->s_first_data_block); + + ar->len = 0; + ext4_get_group_no_and_offset(sb, goal, &group, &blkoff); + for (nr = ext4_get_groups_count(sb); nr > 0; nr--) { + bitmap_bh = ext4_read_block_bitmap(sb, group); + if (IS_ERR(bitmap_bh)) { + *errp = PTR_ERR(bitmap_bh); + pr_warn("Failed to read block bitmap\n"); + return 0; + } + + while (1) { + i = mb_find_next_zero_bit(bitmap_bh->b_data, max, + blkoff); + if (i >= max) + break; + if (ext4_fc_replay_check_excluded(sb, + ext4_group_first_block_no(sb, group) + + EXT4_C2B(sbi, i))) { + blkoff = i + 1; + } else + break; + } + brelse(bitmap_bh); + if (i < max) + break; + + if (++group >= ext4_get_groups_count(sb)) + group = 0; + + blkoff = 0; + } + + if (i >= max) { + *errp = -ENOSPC; + return 0; + } + + block = ext4_group_first_block_no(sb, group) + EXT4_C2B(sbi, i); + ext4_mb_mark_bb(sb, block, 1, true); + ar->len = 1; + + *errp = 0; + return block; +} + +/* + * Main entry point into mballoc to allocate blocks + * it tries to use preallocation first, then falls back + * to usual allocation + */ +ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle, + struct ext4_allocation_request *ar, int *errp) +{ + struct ext4_allocation_context *ac = NULL; + struct ext4_sb_info *sbi; + struct super_block *sb; + ext4_fsblk_t block = 0; + unsigned int inquota = 0; + unsigned int reserv_clstrs = 0; + int retries = 0; + u64 seq; + + might_sleep(); + sb = ar->inode->i_sb; + sbi = EXT4_SB(sb); + + trace_ext4_request_blocks(ar); + if (sbi->s_mount_state & EXT4_FC_REPLAY) + return ext4_mb_new_blocks_simple(ar, errp); + + /* Allow to use superuser reservation for quota file */ + if (ext4_is_quota_file(ar->inode)) + ar->flags |= EXT4_MB_USE_ROOT_BLOCKS; + + if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) { + /* Without delayed allocation we need to verify + * there is enough free blocks to do block allocation + * and verify allocation doesn't exceed the quota limits. + */ + while (ar->len && + ext4_claim_free_clusters(sbi, ar->len, ar->flags)) { + + /* let others to free the space */ + cond_resched(); + ar->len = ar->len >> 1; + } + if (!ar->len) { + ext4_mb_show_pa(sb); + *errp = -ENOSPC; + return 0; + } + reserv_clstrs = ar->len; + if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) { + dquot_alloc_block_nofail(ar->inode, + EXT4_C2B(sbi, ar->len)); + } else { + while (ar->len && + dquot_alloc_block(ar->inode, + EXT4_C2B(sbi, ar->len))) { + + ar->flags |= EXT4_MB_HINT_NOPREALLOC; + ar->len--; + } + } + inquota = ar->len; + if (ar->len == 0) { + *errp = -EDQUOT; + goto out; + } + } + + ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS); + if (!ac) { + ar->len = 0; + *errp = -ENOMEM; + goto out; + } + + ext4_mb_initialize_context(ac, ar); + + ac->ac_op = EXT4_MB_HISTORY_PREALLOC; + seq = this_cpu_read(discard_pa_seq); + if (!ext4_mb_use_preallocated(ac)) { + ac->ac_op = EXT4_MB_HISTORY_ALLOC; + ext4_mb_normalize_request(ac, ar); + + *errp = ext4_mb_pa_alloc(ac); + if (*errp) + goto errout; +repeat: + /* allocate space in core */ + *errp = ext4_mb_regular_allocator(ac); + /* + * pa allocated above is added to grp->bb_prealloc_list only + * when we were able to allocate some block i.e. when + * ac->ac_status == AC_STATUS_FOUND. + * And error from above mean ac->ac_status != AC_STATUS_FOUND + * So we have to free this pa here itself. + */ + if (*errp) { + ext4_mb_pa_put_free(ac); + ext4_discard_allocated_blocks(ac); + goto errout; + } + if (ac->ac_status == AC_STATUS_FOUND && + ac->ac_o_ex.fe_len >= ac->ac_f_ex.fe_len) + ext4_mb_pa_put_free(ac); + } + if (likely(ac->ac_status == AC_STATUS_FOUND)) { + *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs); + if (*errp) { + ext4_discard_allocated_blocks(ac); + goto errout; + } else { + block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); + ar->len = ac->ac_b_ex.fe_len; + } + } else { + if (++retries < 3 && + ext4_mb_discard_preallocations_should_retry(sb, ac, &seq)) + goto repeat; + /* + * If block allocation fails then the pa allocated above + * needs to be freed here itself. + */ + ext4_mb_pa_put_free(ac); + *errp = -ENOSPC; + } + + if (*errp) { +errout: + ac->ac_b_ex.fe_len = 0; + ar->len = 0; + ext4_mb_show_ac(ac); + } + ext4_mb_release_context(ac); + kmem_cache_free(ext4_ac_cachep, ac); +out: + if (inquota && ar->len < inquota) + dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len)); + if (!ar->len) { + if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) + /* release all the reserved blocks if non delalloc */ + percpu_counter_sub(&sbi->s_dirtyclusters_counter, + reserv_clstrs); + } + + trace_ext4_allocate_blocks(ar, (unsigned long long)block); + + return block; +} + +/* + * We can merge two free data extents only if the physical blocks + * are contiguous, AND the extents were freed by the same transaction, + * AND the blocks are associated with the same group. + */ +static inline bool +ext4_freed_extents_can_be_merged(struct ext4_free_data *entry1, + struct ext4_free_data *entry2) +{ + if (entry1->efd_tid != entry2->efd_tid) + return false; + if (entry1->efd_start_cluster + entry1->efd_count != + entry2->efd_start_cluster) + return false; + if (WARN_ON_ONCE(entry1->efd_group != entry2->efd_group)) + return false; + return true; +} + +static inline void +ext4_merge_freed_extents(struct ext4_sb_info *sbi, struct rb_root *root, + struct ext4_free_data *entry1, + struct ext4_free_data *entry2) +{ + entry1->efd_count += entry2->efd_count; + spin_lock(&sbi->s_md_lock); + list_del(&entry2->efd_list); + spin_unlock(&sbi->s_md_lock); + rb_erase(&entry2->efd_node, root); + kmem_cache_free(ext4_free_data_cachep, entry2); +} + +static inline void +ext4_try_merge_freed_extent_prev(struct ext4_sb_info *sbi, struct rb_root *root, + struct ext4_free_data *entry) +{ + struct ext4_free_data *prev; + struct rb_node *node; + + node = rb_prev(&entry->efd_node); + if (!node) + return; + + prev = rb_entry(node, struct ext4_free_data, efd_node); + if (ext4_freed_extents_can_be_merged(prev, entry)) + ext4_merge_freed_extents(sbi, root, prev, entry); +} + +static inline void +ext4_try_merge_freed_extent_next(struct ext4_sb_info *sbi, struct rb_root *root, + struct ext4_free_data *entry) +{ + struct ext4_free_data *next; + struct rb_node *node; + + node = rb_next(&entry->efd_node); + if (!node) + return; + + next = rb_entry(node, struct ext4_free_data, efd_node); + if (ext4_freed_extents_can_be_merged(entry, next)) + ext4_merge_freed_extents(sbi, root, entry, next); +} + +static noinline_for_stack void +ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b, + struct ext4_free_data *new_entry) +{ + ext4_group_t group = e4b->bd_group; + ext4_grpblk_t cluster; + ext4_grpblk_t clusters = new_entry->efd_count; + struct ext4_free_data *entry = NULL; + struct ext4_group_info *db = e4b->bd_info; + struct super_block *sb = e4b->bd_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct rb_root *root = &db->bb_free_root; + struct rb_node **n = &root->rb_node; + struct rb_node *parent = NULL, *new_node; + + BUG_ON(!ext4_handle_valid(handle)); + BUG_ON(e4b->bd_bitmap_folio == NULL); + BUG_ON(e4b->bd_buddy_folio == NULL); + + new_node = &new_entry->efd_node; + cluster = new_entry->efd_start_cluster; + + if (!*n) { + /* first free block exent. We need to + protect buddy cache from being freed, + * otherwise we'll refresh it from + * on-disk bitmap and lose not-yet-available + * blocks */ + folio_get(e4b->bd_buddy_folio); + folio_get(e4b->bd_bitmap_folio); + } + while (*n) { + parent = *n; + entry = rb_entry(parent, struct ext4_free_data, efd_node); + if (cluster < entry->efd_start_cluster) + n = &(*n)->rb_left; + else if (cluster >= (entry->efd_start_cluster + entry->efd_count)) + n = &(*n)->rb_right; + else { + ext4_grp_locked_error(sb, group, 0, + ext4_group_first_block_no(sb, group) + + EXT4_C2B(sbi, cluster), + "Block already on to-be-freed list"); + kmem_cache_free(ext4_free_data_cachep, new_entry); + return; + } + } + + atomic_add(clusters, &sbi->s_mb_free_pending); + if (!entry) + goto insert; + + /* Now try to see the extent can be merged to prev and next */ + if (ext4_freed_extents_can_be_merged(new_entry, entry)) { + entry->efd_start_cluster = cluster; + entry->efd_count += new_entry->efd_count; + kmem_cache_free(ext4_free_data_cachep, new_entry); + ext4_try_merge_freed_extent_prev(sbi, root, entry); + return; + } + if (ext4_freed_extents_can_be_merged(entry, new_entry)) { + entry->efd_count += new_entry->efd_count; + kmem_cache_free(ext4_free_data_cachep, new_entry); + ext4_try_merge_freed_extent_next(sbi, root, entry); + return; + } +insert: + rb_link_node(new_node, parent, n); + rb_insert_color(new_node, root); + + spin_lock(&sbi->s_md_lock); + list_add_tail(&new_entry->efd_list, &sbi->s_freed_data_list[new_entry->efd_tid & 1]); + spin_unlock(&sbi->s_md_lock); +} + +static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block, + unsigned long count) +{ + struct super_block *sb = inode->i_sb; + ext4_group_t group; + ext4_grpblk_t blkoff; + + ext4_get_group_no_and_offset(sb, block, &group, &blkoff); + ext4_mb_mark_context(NULL, sb, false, group, blkoff, count, + EXT4_MB_BITMAP_MARKED_CHECK | + EXT4_MB_SYNC_UPDATE, + NULL); +} + +/** + * ext4_mb_clear_bb() -- helper function for freeing blocks. + * Used by ext4_free_blocks() + * @handle: handle for this transaction + * @inode: inode + * @block: starting physical block to be freed + * @count: number of blocks to be freed + * @flags: flags used by ext4_free_blocks + */ +static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode, + ext4_fsblk_t block, unsigned long count, + int flags) +{ + struct super_block *sb = inode->i_sb; + struct ext4_group_info *grp; + unsigned int overflow; + ext4_grpblk_t bit; + ext4_group_t block_group; + struct ext4_sb_info *sbi; + struct ext4_buddy e4b; + unsigned int count_clusters; + int err = 0; + int mark_flags = 0; + ext4_grpblk_t changed; + + sbi = EXT4_SB(sb); + + if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) && + !ext4_inode_block_valid(inode, block, count)) { + ext4_error(sb, "Freeing blocks in system zone - " + "Block = %llu, count = %lu", block, count); + /* err = 0. ext4_std_error should be a no op */ + goto error_out; + } + flags |= EXT4_FREE_BLOCKS_VALIDATED; + +do_more: + overflow = 0; + ext4_get_group_no_and_offset(sb, block, &block_group, &bit); + + grp = ext4_get_group_info(sb, block_group); + if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) + return; + + /* + * Check to see if we are freeing blocks across a group + * boundary. + */ + if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) { + overflow = EXT4_C2B(sbi, bit) + count - + EXT4_BLOCKS_PER_GROUP(sb); + count -= overflow; + /* The range changed so it's no longer validated */ + flags &= ~EXT4_FREE_BLOCKS_VALIDATED; + } + count_clusters = EXT4_NUM_B2C(sbi, count); + trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters); + + /* __GFP_NOFAIL: retry infinitely, ignore TIF_MEMDIE and memcg limit. */ + err = ext4_mb_load_buddy_gfp(sb, block_group, &e4b, + GFP_NOFS|__GFP_NOFAIL); + if (err) + goto error_out; + + if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) && + !ext4_inode_block_valid(inode, block, count)) { + ext4_error(sb, "Freeing blocks in system zone - " + "Block = %llu, count = %lu", block, count); + /* err = 0. ext4_std_error should be a no op */ + goto error_clean; + } + +#ifdef AGGRESSIVE_CHECK + mark_flags |= EXT4_MB_BITMAP_MARKED_CHECK; +#endif + err = ext4_mb_mark_context(handle, sb, false, block_group, bit, + count_clusters, mark_flags, &changed); + + + if (err && changed == 0) + goto error_clean; + +#ifdef AGGRESSIVE_CHECK + BUG_ON(changed != count_clusters); +#endif + + /* + * We need to make sure we don't reuse the freed block until after the + * transaction is committed. We make an exception if the inode is to be + * written in writeback mode since writeback mode has weak data + * consistency guarantees. + */ + if (ext4_handle_valid(handle) && + ((flags & EXT4_FREE_BLOCKS_METADATA) || + !ext4_should_writeback_data(inode))) { + struct ext4_free_data *new_entry; + /* + * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed + * to fail. + */ + new_entry = kmem_cache_alloc(ext4_free_data_cachep, + GFP_NOFS|__GFP_NOFAIL); + new_entry->efd_start_cluster = bit; + new_entry->efd_group = block_group; + new_entry->efd_count = count_clusters; + new_entry->efd_tid = handle->h_transaction->t_tid; + + ext4_lock_group(sb, block_group); + ext4_mb_free_metadata(handle, &e4b, new_entry); + } else { + if (test_opt(sb, DISCARD)) { + err = ext4_issue_discard(sb, block_group, bit, + count_clusters); + /* + * Ignore EOPNOTSUPP error. This is consistent with + * what happens when using journal. + */ + if (err == -EOPNOTSUPP) + err = 0; + if (err) + ext4_msg(sb, KERN_WARNING, "discard request in" + " group:%u block:%d count:%lu failed" + " with %d", block_group, bit, count, + err); + } + + EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info); + + ext4_lock_group(sb, block_group); + mb_free_blocks(inode, &e4b, bit, count_clusters); + } + + ext4_unlock_group(sb, block_group); + + /* + * on a bigalloc file system, defer the s_freeclusters_counter + * update to the caller (ext4_remove_space and friends) so they + * can determine if a cluster freed here should be rereserved + */ + if (!(flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)) { + if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE)) + dquot_free_block(inode, EXT4_C2B(sbi, count_clusters)); + percpu_counter_add(&sbi->s_freeclusters_counter, + count_clusters); + } + + if (overflow && !err) { + block += count; + count = overflow; + ext4_mb_unload_buddy(&e4b); + /* The range changed so it's no longer validated */ + flags &= ~EXT4_FREE_BLOCKS_VALIDATED; + goto do_more; + } + +error_clean: + ext4_mb_unload_buddy(&e4b); +error_out: + ext4_std_error(sb, err); +} + +/** + * ext4_free_blocks() -- Free given blocks and update quota + * @handle: handle for this transaction + * @inode: inode + * @bh: optional buffer of the block to be freed + * @block: starting physical block to be freed + * @count: number of blocks to be freed + * @flags: flags used by ext4_free_blocks + */ +void ext4_free_blocks(handle_t *handle, struct inode *inode, + struct buffer_head *bh, ext4_fsblk_t block, + unsigned long count, int flags) +{ + struct super_block *sb = inode->i_sb; + unsigned int overflow; + struct ext4_sb_info *sbi; + + sbi = EXT4_SB(sb); + + if (bh) { + if (block) + BUG_ON(block != bh->b_blocknr); + else + block = bh->b_blocknr; + } + + if (sbi->s_mount_state & EXT4_FC_REPLAY) { + ext4_free_blocks_simple(inode, block, EXT4_NUM_B2C(sbi, count)); + return; + } + + might_sleep(); + + if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) && + !ext4_inode_block_valid(inode, block, count)) { + ext4_error(sb, "Freeing blocks not in datazone - " + "block = %llu, count = %lu", block, count); + return; + } + flags |= EXT4_FREE_BLOCKS_VALIDATED; + + ext4_debug("freeing block %llu\n", block); + trace_ext4_free_blocks(inode, block, count, flags); + + if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) { + BUG_ON(count > 1); + + ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA, + inode, bh, block); + } + + /* + * If the extent to be freed does not begin on a cluster + * boundary, we need to deal with partial clusters at the + * beginning and end of the extent. Normally we will free + * blocks at the beginning or the end unless we are explicitly + * requested to avoid doing so. + */ + overflow = EXT4_PBLK_COFF(sbi, block); + if (overflow) { + if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) { + overflow = sbi->s_cluster_ratio - overflow; + block += overflow; + if (count > overflow) + count -= overflow; + else + return; + } else { + block -= overflow; + count += overflow; + } + /* The range changed so it's no longer validated */ + flags &= ~EXT4_FREE_BLOCKS_VALIDATED; + } + overflow = EXT4_LBLK_COFF(sbi, count); + if (overflow) { + if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) { + if (count > overflow) + count -= overflow; + else + return; + } else + count += sbi->s_cluster_ratio - overflow; + /* The range changed so it's no longer validated */ + flags &= ~EXT4_FREE_BLOCKS_VALIDATED; + } + + if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) { + int i; + int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA; + + for (i = 0; i < count; i++) { + cond_resched(); + if (is_metadata) + bh = sb_find_get_block_nonatomic(inode->i_sb, + block + i); + ext4_forget(handle, is_metadata, inode, bh, block + i); + } + } + + ext4_mb_clear_bb(handle, inode, block, count, flags); +} + +/** + * ext4_group_add_blocks() -- Add given blocks to an existing group + * @handle: handle to this transaction + * @sb: super block + * @block: start physical block to add to the block group + * @count: number of blocks to free + * + * This marks the blocks as free in the bitmap and buddy. + */ +int ext4_group_add_blocks(handle_t *handle, struct super_block *sb, + ext4_fsblk_t block, unsigned long count) +{ + ext4_group_t block_group; + ext4_grpblk_t bit; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_buddy e4b; + int err = 0; + ext4_fsblk_t first_cluster = EXT4_B2C(sbi, block); + ext4_fsblk_t last_cluster = EXT4_B2C(sbi, block + count - 1); + unsigned long cluster_count = last_cluster - first_cluster + 1; + ext4_grpblk_t changed; + + ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1); + + if (cluster_count == 0) + return 0; + + ext4_get_group_no_and_offset(sb, block, &block_group, &bit); + /* + * Check to see if we are freeing blocks across a group + * boundary. + */ + if (bit + cluster_count > EXT4_CLUSTERS_PER_GROUP(sb)) { + ext4_warning(sb, "too many blocks added to group %u", + block_group); + err = -EINVAL; + goto error_out; + } + + err = ext4_mb_load_buddy(sb, block_group, &e4b); + if (err) + goto error_out; + + if (!ext4_sb_block_valid(sb, NULL, block, count)) { + ext4_error(sb, "Adding blocks in system zones - " + "Block = %llu, count = %lu", + block, count); + err = -EINVAL; + goto error_clean; + } + + err = ext4_mb_mark_context(handle, sb, false, block_group, bit, + cluster_count, EXT4_MB_BITMAP_MARKED_CHECK, + &changed); + if (err && changed == 0) + goto error_clean; + + if (changed != cluster_count) + ext4_error(sb, "bit already cleared in group %u", block_group); + + ext4_lock_group(sb, block_group); + mb_free_blocks(NULL, &e4b, bit, cluster_count); + ext4_unlock_group(sb, block_group); + percpu_counter_add(&sbi->s_freeclusters_counter, + changed); + +error_clean: + ext4_mb_unload_buddy(&e4b); +error_out: + ext4_std_error(sb, err); + return err; +} + +/** + * ext4_trim_extent -- function to TRIM one single free extent in the group + * @sb: super block for the file system + * @start: starting block of the free extent in the alloc. group + * @count: number of blocks to TRIM + * @e4b: ext4 buddy for the group + * + * Trim "count" blocks starting at "start" in the "group". To assure that no + * one will allocate those blocks, mark it as used in buddy bitmap. This must + * be called with under the group lock. + */ +static int ext4_trim_extent(struct super_block *sb, + int start, int count, struct ext4_buddy *e4b) +__releases(bitlock) +__acquires(bitlock) +{ + struct ext4_free_extent ex; + ext4_group_t group = e4b->bd_group; + int ret = 0; + + trace_ext4_trim_extent(sb, group, start, count); + + assert_spin_locked(ext4_group_lock_ptr(sb, group)); + + ex.fe_start = start; + ex.fe_group = group; + ex.fe_len = count; + + /* + * Mark blocks used, so no one can reuse them while + * being trimmed. + */ + mb_mark_used(e4b, &ex); + ext4_unlock_group(sb, group); + ret = ext4_issue_discard(sb, group, start, count); + ext4_lock_group(sb, group); + mb_free_blocks(NULL, e4b, start, ex.fe_len); + return ret; +} + +static ext4_grpblk_t ext4_last_grp_cluster(struct super_block *sb, + ext4_group_t grp) +{ + unsigned long nr_clusters_in_group; + + if (grp < (ext4_get_groups_count(sb) - 1)) + nr_clusters_in_group = EXT4_CLUSTERS_PER_GROUP(sb); + else + nr_clusters_in_group = (ext4_blocks_count(EXT4_SB(sb)->s_es) - + ext4_group_first_block_no(sb, grp)) + >> EXT4_CLUSTER_BITS(sb); + + return nr_clusters_in_group - 1; +} + +static bool ext4_trim_interrupted(void) +{ + return fatal_signal_pending(current) || freezing(current); +} + +static int ext4_try_to_trim_range(struct super_block *sb, + struct ext4_buddy *e4b, ext4_grpblk_t start, + ext4_grpblk_t max, ext4_grpblk_t minblocks) +__acquires(ext4_group_lock_ptr(sb, e4b->bd_group)) +__releases(ext4_group_lock_ptr(sb, e4b->bd_group)) +{ + ext4_grpblk_t next, count, free_count, last, origin_start; + bool set_trimmed = false; + void *bitmap; + + if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) + return 0; + + last = ext4_last_grp_cluster(sb, e4b->bd_group); + bitmap = e4b->bd_bitmap; + if (start == 0 && max >= last) + set_trimmed = true; + origin_start = start; + start = max(e4b->bd_info->bb_first_free, start); + count = 0; + free_count = 0; + + while (start <= max) { + start = mb_find_next_zero_bit(bitmap, max + 1, start); + if (start > max) + break; + + next = mb_find_next_bit(bitmap, last + 1, start); + if (origin_start == 0 && next >= last) + set_trimmed = true; + + if ((next - start) >= minblocks) { + int ret = ext4_trim_extent(sb, start, next - start, e4b); + + if (ret && ret != -EOPNOTSUPP) + return count; + count += next - start; + } + free_count += next - start; + start = next + 1; + + if (ext4_trim_interrupted()) + return count; + + if (need_resched()) { + ext4_unlock_group(sb, e4b->bd_group); + cond_resched(); + ext4_lock_group(sb, e4b->bd_group); + } + + if ((e4b->bd_info->bb_free - free_count) < minblocks) + break; + } + + if (set_trimmed) + EXT4_MB_GRP_SET_TRIMMED(e4b->bd_info); + + return count; +} + +/** + * ext4_trim_all_free -- function to trim all free space in alloc. group + * @sb: super block for file system + * @group: group to be trimmed + * @start: first group block to examine + * @max: last group block to examine + * @minblocks: minimum extent block count + * + * ext4_trim_all_free walks through group's block bitmap searching for free + * extents. When the free extent is found, mark it as used in group buddy + * bitmap. Then issue a TRIM command on this extent and free the extent in + * the group buddy bitmap. + */ +static ext4_grpblk_t +ext4_trim_all_free(struct super_block *sb, ext4_group_t group, + ext4_grpblk_t start, ext4_grpblk_t max, + ext4_grpblk_t minblocks) +{ + struct ext4_buddy e4b; + int ret; + + trace_ext4_trim_all_free(sb, group, start, max); + + ret = ext4_mb_load_buddy(sb, group, &e4b); + if (ret) { + ext4_warning(sb, "Error %d loading buddy information for %u", + ret, group); + return ret; + } + + ext4_lock_group(sb, group); + + if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) || + minblocks < EXT4_SB(sb)->s_last_trim_minblks) + ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks); + else + ret = 0; + + ext4_unlock_group(sb, group); + ext4_mb_unload_buddy(&e4b); + + ext4_debug("trimmed %d blocks in the group %d\n", + ret, group); + + return ret; +} + +/** + * ext4_trim_fs() -- trim ioctl handle function + * @sb: superblock for filesystem + * @range: fstrim_range structure + * + * start: First Byte to trim + * len: number of Bytes to trim from start + * minlen: minimum extent length in Bytes + * ext4_trim_fs goes through all allocation groups containing Bytes from + * start to start+len. For each such a group ext4_trim_all_free function + * is invoked to trim all free space. + */ +int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) +{ + unsigned int discard_granularity = bdev_discard_granularity(sb->s_bdev); + struct ext4_group_info *grp; + ext4_group_t group, first_group, last_group; + ext4_grpblk_t cnt = 0, first_cluster, last_cluster; + uint64_t start, end, minlen, trimmed = 0; + ext4_fsblk_t first_data_blk = + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); + ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es); + int ret = 0; + + start = range->start >> sb->s_blocksize_bits; + end = start + (range->len >> sb->s_blocksize_bits) - 1; + minlen = EXT4_NUM_B2C(EXT4_SB(sb), + range->minlen >> sb->s_blocksize_bits); + + if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) || + start >= max_blks || + range->len < sb->s_blocksize) + return -EINVAL; + /* No point to try to trim less than discard granularity */ + if (range->minlen < discard_granularity) { + minlen = EXT4_NUM_B2C(EXT4_SB(sb), + discard_granularity >> sb->s_blocksize_bits); + if (minlen > EXT4_CLUSTERS_PER_GROUP(sb)) + goto out; + } + if (end >= max_blks - 1) + end = max_blks - 1; + if (end <= first_data_blk) + goto out; + if (start < first_data_blk) + start = first_data_blk; + + /* Determine first and last group to examine based on start and end */ + ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start, + &first_group, &first_cluster); + ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end, + &last_group, &last_cluster); + + /* end now represents the last cluster to discard in this group */ + end = EXT4_CLUSTERS_PER_GROUP(sb) - 1; + + for (group = first_group; group <= last_group; group++) { + if (ext4_trim_interrupted()) + break; + grp = ext4_get_group_info(sb, group); + if (!grp) + continue; + /* We only do this if the grp has never been initialized */ + if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) { + ret = ext4_mb_init_group(sb, group, GFP_NOFS); + if (ret) + break; + } + + /* + * For all the groups except the last one, last cluster will + * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to + * change it for the last group, note that last_cluster is + * already computed earlier by ext4_get_group_no_and_offset() + */ + if (group == last_group) + end = last_cluster; + if (grp->bb_free >= minlen) { + cnt = ext4_trim_all_free(sb, group, first_cluster, + end, minlen); + if (cnt < 0) { + ret = cnt; + break; + } + trimmed += cnt; + } + + /* + * For every group except the first one, we are sure + * that the first cluster to discard will be cluster #0. + */ + first_cluster = 0; + } + + if (!ret) + EXT4_SB(sb)->s_last_trim_minblks = minlen; + +out: + range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits; + return ret; +} + +/* Iterate all the free extents in the group. */ +int +ext4_mballoc_query_range( + struct super_block *sb, + ext4_group_t group, + ext4_grpblk_t first, + ext4_grpblk_t end, + ext4_mballoc_query_range_fn meta_formatter, + ext4_mballoc_query_range_fn formatter, + void *priv) +{ + void *bitmap; + ext4_grpblk_t start, next; + struct ext4_buddy e4b; + int error; + + error = ext4_mb_load_buddy(sb, group, &e4b); + if (error) + return error; + bitmap = e4b.bd_bitmap; + + ext4_lock_group(sb, group); + + start = max(e4b.bd_info->bb_first_free, first); + if (end >= EXT4_CLUSTERS_PER_GROUP(sb)) + end = EXT4_CLUSTERS_PER_GROUP(sb) - 1; + if (meta_formatter && start != first) { + if (start > end) + start = end; + ext4_unlock_group(sb, group); + error = meta_formatter(sb, group, first, start - first, + priv); + if (error) + goto out_unload; + ext4_lock_group(sb, group); + } + while (start <= end) { + start = mb_find_next_zero_bit(bitmap, end + 1, start); + if (start > end) + break; + next = mb_find_next_bit(bitmap, end + 1, start); + + ext4_unlock_group(sb, group); + error = formatter(sb, group, start, next - start, priv); + if (error) + goto out_unload; + ext4_lock_group(sb, group); + + start = next + 1; + } + + ext4_unlock_group(sb, group); +out_unload: + ext4_mb_unload_buddy(&e4b); + + return error; +} + +#ifdef CONFIG_EXT4_KUNIT_TESTS +#include "mballoc-test.c" +#endif -- 2.43.0